Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Serial coagulation studies were performed in 26 pediatric patients with acute lymphoblastic leukemia during initial induction therapy with vincristine, prednisone, and L-asparaginase. Prolongation of screening coagulation tests was frequent: prothrombin time (in 16 of 26 patients), partial thromboplastin time (23/26) and thrombin time (21/26). In all 26 patients fibrinogen levels fell below .20 g/100 ml and 16 had levels below .10 g/100 ml. Sixteen patients had plasma coagulation factor assays performed. In these 16 patients, Factor XI was less than 40% in 14 and Factor XI was less than 70% in 9, with only a few scattered low levels of other factors. There were no clinical bleeding episodes. Coagulation abnormalities returned to normal at the completion of L-asparaginase therapy while the patients remained on vincristine and prednisone.
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PMID:The effect of L-asparaginase of plasma coagulation factors in acute lymphoblastic leukemia. 26 3

Serum complement studies were carried out in five children with acute lymphocytic leukemia. During therapy with L-asparaginase, prednisone and vincristine, hypocomplementemia developed in all patients, and disappeared within 2 weeks after the discontinuation of L-asparaginase. Complement breakdown products were not present in plasma. The changes of serum complement levels paralleled those of plasma fibrinogen. These findings suggest that the hypocomplementemia observed in these patients may be related to impaired protein synthesis induced by L-asparaginase.
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PMID:L-asparaginase-induced hypocomplementemia in acute lymphocytic leukemia (ALL) of childhood. 29 75

This paper is concerned with the evaluation of the in vivo performance characteristics of reconstituted bovine collagen as an insoluble carrier matrix fro therapeutic enzymes. The enzyme that was chosen as a model for this evaluation was E. coli L-asparaginase, which has been widely investigated as a soluble chemotherapeutic agent for the treatment of acute lymphocytic leukemia in humans (Oettgen et al., Cancer Res., 27, 2619, 1967 ; Beard et al., Brit. Med. J., 1, 191, 1970; Ohmuma et al., Cancer Res., 30, 2297, 1970). The results presented here were obtained from perfusion trials with a collagen-asparaginase reactor incorporated into an extracorporeal circuit attached to the vascular systems of healthy mongrel dogs. A series of 1-2 hr perfusions were conducted with a single collagen-asparaginase membrane over a period of 4 months. Serum asparagine levels were reduced by more than 98% after 15-30 min perfusion time. Red blood cell (RBC), hemoglobin, hematocrit, and fibrinogen values remained constant during each perfusion. An average decrease of 48% in white blood cell (WBC) and 24% in platelet levels was observed, but these values began to rise slowly even before cessation of the perfusion. No serious toxic or antigenic reactions or mechanical or clotting difficulties were observed. In vitro activity, when assayed between perfusions, remained constant over a period of 4 months of intermittent use and storage. The potential advantages of collagen-enzyme complexes for the administration of therapeutic enzymes is discussed.
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PMID:Perfusion trials with a collagen-immobilized enzyme in an extracorporeal reactor: activity, stability, and biocompatibility. 84 82

Immobilized asparaginase was prepared by embedding asparaginase (which is effective for remission in children with leukemia) into fibrin polymer formed by fibrinogen-fibrin conversion in the presence of thrombin. The immobilized asparaginase film did not dissolve in 6 mol/1 urea, suggesting that blood coagulation factor XIII participates in the cross-linking between fibrins and between fibrin and asparaginase.
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PMID:Immobilized L-asparginase embedded in fibrin polymer. 109 44

A 48-year-old female received serial combination chemotherapy including L-asparaginase (L-ASP) for acute lymphoblastic leukemia. After administration of L-ASP, the prothrombin time and activated partial thromboplastin time were prolonged, while fibrinogen and antithrombin III levels markedly decreased, so she was given fresh frozen plasma (FFP). But subsequently, she developed cerebral infarction in the left parietal region and further hemorrhagic infarction in the right parietal region, and died. Autopsy revealed superior sagittal sinus thrombosis and bilateral cerebral infarction, but no obvious thrombus in other organs. Coagulopathy following L-ASP therapy is well-known. In this case, the coagulation studies at the first attack showed that the plasma protein levels of coagulation and fibrinolysis factors decreased in spite of administration of FFP. Fibrin-fibrinogen degradation products (FDP) slightly increased. However there were no significant abnormalities in the platelet count, nor soluble fibrin monomer, which suggested no evidence of disseminated intravascular coagulation. Thus, these findings suggest that L-ASP might be associated with the pathogenesis of thrombosis in this case.
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PMID:[Superior sagittal sinus thrombosis following L-asparaginase therapy of acute lymphoblastic leukemia]. 157 39

Ten healthy dogs and 10 dogs with multicentric lymphoma were given a single dose of L-asparaginase at a rate of 10,000 IU/m2 of body surface. Assessment of concentrations of contributors to the coagulation process and of the ability to coagulate including antithrombin III, one-stage prothrombin time, prothrombin-proconvertin time, activated partial thromboplastin time, plasminogen, fibrinogen, and platelet number were performed prior to drug administration (day 0). These tests were repeated 24 hours (day 1), 48 hours (day 2), and 7 days after treatment with L-asparaginase. Antithrombin-III concentrations were significantly lower in the dogs with lymphoma than in healthy dogs on days 0, 1, 2, and 7; however, with the exception of day 1, mean values remained within normal limits. There was also a difference between the 2 groups in prothrombin/proconvertin values on day 7 and in platelet number on day 2, with the lymphoma group having significantly shorter prothrombin/proconvertin time than healthy dogs, and the difference in platelet numbers being associated with increased counts in the healthy dogs. Data obtained from the healthy dogs and dogs with lymphoma for each coagulation test were pooled for each treatment day (0, 1, 2, and 7), and day-0 values for each coagulation test were compared with data obtained on days 1, 2, and 7. Antithrombin-III concentration on day 7 was significantly lower than on day 0, prothrombin/proconvertin time on day 1 was significantly longer than on day 0, and fibrinogen concentrations on days 1 and 2 were significantly lower than on day 0.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of single-dose L-asparaginase on coagulation values in healthy dogs and dogs with lymphoma. 158 32

42 dogs with non-Hodgkin's lymphoma (NHL) were randomized for treatment with either PEG-L-asparaginase 10 IU/kg intramuscularly (n = 22) or L-asparaginase 400 IU/kg intraperitoneally (n = 20). Another 20 dogs were treated with either PEG-L-asparaginase 30 IU/kg (n = 10) or L-asparaginase 400 IU/kg (n = 10). Each treatment protocol consisted of two asparaginase treatments followed by a 10-week period of induction chemotherapy and then maintenance on asparaginase until progression occurred. No significant differences were found between treatments in the response rates after 2 weeks of asparaginase therapy or in the time to relapse, the time to treatment failure or the remission period. The reaction to asparaginase after the initial 2 weeks was a prognostic factor for the total duration of remission under asparaginase maintenance therapy. No side-effects were noted in the dogs treated with PEG-L-asparaginase, whereas 14 (48%) of the L-asparaginase treated dogs had side-effects related to this drug, including anaphylactic shock (9), anorexia or vomiting (4), hypersensitivity-related oedema (3), seizures (1) and acute pancreatitis (1). No abnormalities in clotting times, fibrinogen levels or antithrombin-III levels were found in any of the 62 dogs. PEG-L-asparaginase has the same anti-tumour activity as native L-asparaginase in dogs with NHL, but lacks side-effects.
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PMID:Polyethylene glycol-L-asparaginase versus native L-asparaginase in canine non-Hodgkin's lymphoma. 214 33

To evaluate the occurrence of hypercoagulability during treatment with L-asparaginase (L-ase), thrombin-antithrombin complex (TAT) and D-dimer levels in plasma were serially measured in 15 consecutive adult patients with acute lymphoblastic leukaemia or lymphoblastic lymphoma who had recently completed a chemotherapy cycle with cytosine arabinoside and methotrexate. The first eight patients (group A) received i.v. L-ase alone (20,000 U/m2 on alternate days over 10 d); the last seven patients (group B) received, in addition to L-ase, bolus injection of antithrombin concentrate (2000 U) on alternate days for a total of six administrations, beginning with the second L-ase infusion. Increased levels of TAT (P less than 0.05) and D-dimer (P less than 0.01) were observed prior to L-ase, possibly related to inflammation and cytolysis secondary to previous chemotherapy. In patients treated with L-ase alone, further elevation of TAT (P less than 0.05) and persistence of increased D-dimer were observed, associated with marked reduction of the anticoagulant activities of protein C, protein S and antithrombin III. At variance, in patients receiving antithrombin III supplementation there was no increase of TAT and a normalization of D-dimer levels occurred during L-ase treatment. In these patients, mean plasma antithrombin III activity was maintained at levels higher than 70% of normal throughout the treatment. The rate of decline of fibrinogen, factor IX, protein C and protein S was unaffected by antithrombin III supplementation, indicating that hypercoagulability has little if any relevance for the reduction of coagulation factors and inhibitors induced by L-ase treatment. The usefulness of antithrombin III concentrates in preventing thromboembolic complications in patients submitted to L-ase treatment remains to be determined.
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PMID:Hypercoagulability during L-asparaginase treatment: the effect of antithrombin III supplementation in vivo. 218 89

A polyethylene glycol conjugate of L-asparaginase (PEGLA) was administered to 21 patients with refractory non-Hodgkin's lymphoma. The dose given was 2,000 mu/m2 intramuscularly every 2 weeks. Eligibility required at least one prior trial of chemotherapy and ambulatory performance status. At entry, all patients had measurable lesions and documented disease progression. The median age of the patients was 61 years; 18 (86%) were ambulatory with minimal symptoms, 12 patients (57%) had 3 or more prior regimens, and 13 (62%) had stage IV disease. Histologic subtype was low grade in 11 patients (52%), intermediate in 7 (33%), high grade in 2 (10%) and unclassifiable in one (5%). There were two partial responses (11%) noted (95% confidence interval of response of 1-30%). Eleven patients (52%) were removed from study due to disease progression. Nine patients (43%), required removal for toxicity (7 for protracted nausea and vomiting and 2 for confusion). One patient died of sepsis while on study but this was not considered drug related. Almost one third of patients complained of fatigue or loss of appetite. Nausea and vomiting occurred in approximately half the patients and was moderate to severe in 9. Diarrhea and abdominal pain were also noted in one-third of those treated. Changes in the partial thromboplastin time and fibrinogen were noted in most patients but resulted in no bleeding complications. In this trial, PEGLA displayed modest activity in a heterogenous group of patients with progressive non-Hodgkin's lymphoma.
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PMID:A phase II trial of PEG-L-asparaginase in the treatment of non-Hodgkins lymphoma. 234 67

Alpha-2-antiplasmin, a major inhibitor of fibrinolysis, is synthesized in the liver and occurs in blood in two molecular forms: a very active plasminogen-binding (PB) form and a less active nonplasminogen-binding (NPB) form. This study investigates the origin and mutual relationship of these two forms in vivo and in vitro. Despite wide variation in plasma concentration of the inhibitor (16% to 138%), the ratio between the two forms in vivo was found to be, in the main, constant among healthy volunteers, heterozygotes for a congenital deficiency of alpha-2-antiplasmin, and patients with a stable liver cirrhosis: PB/NPB = 2.41 +/- 0.34 (SD). Resynthesis after depletion or increased synthesis in the acute-phase reaction showed a specific increase of the PB form of the molecule in blood after discontinuation of L-asparaginase or streptokinase therapy and after myocardial infarction. In vitro studies demonstrated that only the PB form was present after one day in the culture medium of the human cell line Hep G2, while the NPB form appeared after 11 days. Clearance after inhibition of synthesis by L-asparaginase therapy revealed a more rapid decrease in the PB form relative to the NPB form in blood, demonstrated by a change in the PB-NPB ratio from 2.86 +/- 0.55 to 1.74 +/- 0.24 (mean of 6, SD). An apparently spontaneous first order conversion from the PB to NPB form, with an apparent half-life of about eight days, was demonstrated at 37 degrees C in plasma and serum in vitro. The conversion was found to be temperature dependent and uninfluenced by the fibrinolytic components fibrinogen, fibrin, and plasminogen. Additions of a variety of enzymes or inhibitors did not interfere with the process. These results demonstrate that the PB form of alpha-2-antiplasmin is produced by the liver and that the NPB form is formed in the circulation.
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PMID:The mutual relationship between the two molecular forms of the major fibrinolysis inhibitor alpha-2-antiplasmin in blood. 241 96


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