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

---

Query: EC:3.5.1.1 (asparaginase)
2,695 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Short courses of cytosine arabinoside (Ara-C), cyclophosphamide, and L-asparaginase were given to seven children with newly diagnosed acute lymphocytic leukemia, who had failed to remit on standard remission induction therapy. These 4-day courses of Ara-C and cyclophophamide followed by 4 days of L-asparaginase were repeated at 3- to 4-week intervals for two or four courses. Complete remission occurred in six patients. The median duration of remission was 94+ days, on various maintenance regimens. The most serious side effect was neutropenia. This combination of these three drugs appears to be effective remission-induction therapy for children with ALL with unfavorable prognostic features.
...
PMID:Combination chemotherapy for children with acute lymphocytic leukemia who fail to respond to standard remission-induction therapy. 105 44

Of 4 lines of myelogenous rat leukemias induced by N-nitrosobutylurea (NBU), DBLA-6 was selected as a screening model for antileukemic agents because of the following characteristics: a) High transplantability either by intravenous (i.v.) or intraperitoneal (i.p.) inoculation; b) linear relationship between inoculum size and survival time; c) marked increase of leucocyte counts in the peripheral blood as the tumor progresses after intravenous inoculation. To investigate reliability in its predicting clinical efficacy, its sensitivity to known antileukemics was studied. To determine the effects, a change of leucocyte counts in the peripheral blood together with the prolongation of life span was checked in the following systems; i.v.-i.v. (i.v.-inoculation, i.v.-injection), i.v.-i.p., i.p.-i.p., i.p.-i.v. Fifty percent cure was obtained with Vincristine, Vinblastine, Daunorubicin, 6-Mercaptopurine, and alkylating agent 838D or 864T. The success of treatment was measured by decrease of leucocytes. Methotrexate, cytosine arabinoside (Ara-C), and cyclophosphamide showed only poor effects, and Mitomycin C, L-asparaginase, and Bleomycin were ineffective. In addition, the chemotherapeutic effects of Vincristine and 864 on this leukemia were quite dependend both on the route of drug injection and on the site of tumor inoculation. Subsequently, our studies are being extended to cover the correlation between drug distribution and tumor localization or dissemination.
...
PMID:Sensitivity of DBLA-6 leukemia of rats to known antitumor agents in relation to their clinical effects. 116 99

Cytosine arabinoside (ara-C) is one of the most active compounds in the treatment of acute leukemias. In the majority of current protocols ara-C is combined with other cytotoxic agents in an attempt to increase antileukemic activity. The present study investigated the impact of etoposide, teniposide, amsacrine, mitoxantrone, anthracyclines, and asparaginase on the cellular accumulation of ara-C and its intracellular metabolism in order to provide a better rationale for combination therapy. Intracellular accumulation and phosphorylation of ara-C were determined in peripheral blast cells from twenty patients with acute leukemias after exposure to 1 and 10 mumol/l ara-C alone and after preincubation with 1 and 10 micrograms/ml etoposide, 10 and 100 micrograms/ml teniposide, 10 mumol/l amsacrine, 500 ng/ml mitoxantrone (or daunorubicin or doxorubicin) or 10 mumol/l asparaginase. Ara-C accumulation at 10 mumol/l was decreased by 1 microgram/ml etoposide (67 +/- 18% of control), 10 micrograms/ml etoposide (30 +/- 22%), 10 micrograms/ml teniposide (12 +/- 23%), 100 micrograms/ml teniposide (10 +/- 18%), and amsacrine (51 +/- 21%). Intracellular ara-CTP formation was determined at an extracellular concentration of 10 mumol/l and preincubation with these drugs. The intracellular formation of ara-CTP was decreased by 1 microgram/ml etoposide (77 +/- 15% of control), 10 micrograms/ml etoposide (32 +/- 22%), 10 micrograms/ml teniposide (10 +/- 9%), 100 micrograms/ml teniposide (0 +/- 0%), but not by amsacrine. These data indicate that prior exposure to etoposide and teniposide influence ara-C metabolism and possibly cytotoxicity, and thus should not immediately precede ara-C administration in clinical trials.
...
PMID:Intracellular cytosine arabinoside accumulation and cytosine arabinoside triphosphate formation in leukemic blast cells is inhibited by etoposide and teniposide. 160 95

Two patients with hematological malignancies were successfully treated with monomethoxypolyethylene glycol-conjugated Escherichia coli L-asparaginase (PEG2-ASP), which reportedly lacks both antigenicity and immunogenicity but retains catalytic activity as well as slow clearance in an experimental animal model. A 20-year-old male patient with leukemic lymphoma was refractory to conventional chemotherapy but responsive to L-asparaginase (L-ASP) followed, however, by severe adverse effects. On relapse, an intravenous infusion of 100-200 IU/day dose of PEG2-ASP alone led to a complete remission 2 months later without hypersensitivity or other significant adverse reactions. Surprisingly, he remained in a complete remission for over one year with a regular weekly infusion of PEG2-ASP, combined with a weekly small dose of Ara-C. During this period, blood asparagine was not detectable. The other patient, a 64-year-old woman with chronic myelogenous leukemia in blast crisis achieved, within 6 weeks, a complete remission with twice-weekly infusions of PEG2-ASP. Thus, PEG2-ASP is a highly effective antitumor agent overcoming the limitations in therapeutic use of L-ASP.
...
PMID:High efficacy of monomethoxypolyethylene glycol-conjugated L-asparaginase (PEG2-ASP) in two patients with hematological malignancies. 186 35

In June 1984, the Pediatric Oncology Group (POG) initiated a pilot study (8498) using high-dose cytarabine (HdA; 3 g/m2) for intensification of early therapy in childhood acute myelogenous leukemia (AML) (group I). Remission induction therapy consisted of two courses of daunorubicin, cytarabine (Ara-C), and thioguanine (DAT). Postremission therapy consisted of four sequential courses, each consisting of (1) four doses of HdA (HdA4) followed by asparaginase (L-Asp), (2) etoposide (VP) plus azacytidine (Az), (3) prednisone, vincristine, methotrexate, and mercaptopurine (POMP), and (4) Ara-C daily for 5 days by continuous infusion. Six doses of intrathecal Ara-C were given for CNS prophylaxis. In December 1986, the protocol was amended (group II) to substitute six doses of HdA (HdA6) for the second DAT (two + five) induction course; postinduction, a single course of HdA6 was given instead of four HdA/L-Asp courses, and the remainder of the therapy was unchanged. One hundred forty group I patients and 145 group II patients were assessable. The two groups were similar with regard to clinical prognostic groups. No significant differences were noted in the two groups with regard to remission induction (85% [SE = 2%] in each group), induction deaths (6.5% v 7.0%), or deaths in remission (one in each group). Cerebellar toxicity was reported in three patients in group II (with HdA6) but none in group I (HdA4). At present, patients who received HdA6 (group II) had higher event-free survival than patients in group I (EFS at 3 years, 34% [SE = 11%] v 29% [SE = 4%]), and disease-free survival (DFS at 3 years, 42% [SE = 14%] v 34% [SE = 4%]), but the differences were not statistically significant. In both groups, children less than 2 years and those with WBCs less than 100,000/microL had significantly better outcome (EFS of 55% [SE = 10%] and 36% [SE = 5%] at 3 years, respectively) than children greater than or equal to 2 years and those with WBCs greater than or equal to 100,000/microL (EFS of 27% [SE = 5%] and 20% [SE = 9%] at 3 years, respectively.
...
PMID:High-dose cytarabine for intensification of early therapy of childhood acute myeloid leukemia: a Pediatric Oncology Group study. 206 54

The knowledge about drug resistance in childhood leukemias and acute lymphoblastic leukemia (ALL) in general is limited. This is because of the lack of a suitable in vitro drug sensitivity assay, which is in part due to low in vitro ALL cell survival. We recently adapted the highly efficient 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay to test cells from ALL patients and showed that its results were comparable with those of the DiSC assay, up to now the most valid but laborious assay. In this study, in vitro drug sensitivity was assessed in cells from 82 children with leukemia, 79 of whom had ALL, with the MTT assay. Dose response curves were obtained for 6-mercaptopurine, 6-thioguanine (6-TG), prednisolone (Pred), daunorubicin (DNR), vincristine (VCR), cytosine arabinoside (Ara-C), L-asparaginase (L-Asp), mafosfamide, and mustine. A cytotoxic effect of methotrexate could be detected in only a few cases. Large interindividual differences in drug sensitivity were detected. Compared with leukemia cells from newly diagnosed patients, leukemia cells from relapsed patients were significantly more in vitro resistant to 6-TG, Pred, Ara-C, mafosfamide and mustine but not to DNR, VCR, and L-Asp. Improvements of culture medium and methods to increase MTT reduction were studied. From 10 components tested, addition of insulin and bovine serum albumin to serum-containing medium improved ALL cell survival. Addition of succinate did not increase the amount of MTT reduction. We conclude that the in vitro MTT assay highly facilitates large-scale studies on drug resistance of ALL patients that can lead to rational improvements in existing treatment protocols.
...
PMID:In vitro drug sensitivity of cells from children with leukemia using the MTT assay with improved culture conditions. 225 5

The aim of study LAL 17/84 was to reduce the number of relapses by intensifying initial treatment. Patients were classified as high (HR) and standard-risk (SR) groups following the established risk index. Early response, after 2 weeks of treatment was also considered. SR protocol includes a ten-week induction and CNS prophylaxis phase: in the first 5 weeks, prednisolone (PRED), vincristine (VCR), daunorubicin (DAUNO) and asparaginase (ASPAR) are given; in the last 5 weeks two intravenous infusions of Ara-C and three of intermediate dose (ID) methotrexate (MTX) are administered simultaneously with 5 it injections of both drugs. CNS prophylaxis is completed with 5 further it injections: one at the beginning and 4 at monthly intervals from the 3rd to the 6th months. In the HR protocol, the initial phase lasts 16 weeks: in the first 5 the same drugs as in SR are used but doses of PRED and ASPAR are higher. CNS prophylaxis includes holocranial radiotherapy (18 Gy), 2 iv infusions of Ara-C and a further 2 of MTX ID and 6 it doses of MTX and Ara-C. Finally, a consolidation phase of PRED, VCR (3 doses), tenoposide (3 doses) and cyclophosphamide is given. Complementary chemotherapy in both protocols consists of daily mercaptopurine and weekly MTX for 2 years; moreover, the randomized half of the patients received monthly reinforcements with PRED, VCR (and DAUNO in HR group) for 4 months. Between Oct. 83 and Nov. 87,87 patients with ages between 3 months and 15 years were enrolled; 86 are evaluable. All achieved remission.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:[Intensification of the initial treatment in acute lymphoblastic leukemias of middle and high risk in children]. 265 13

A 71-year-old female was diagnosed as hypoplastic leukemia (ALL, L 2). Vitamin D3 (D3) therapy with alfacalcidol was successful and remission continued for approximately 4 months. However, the leukemia became refractory to D3, and low dose Ara-C combined with D3 was ineffective. Combined chemotherapy with vincristine, cyclophosphamide, L-asparaginase and prednisolone, low dose aclarubicin, OK-432 and etretinate ended in a failure. Treatment with mepitiostane was started and 1 month later obvious elevation of hemoglobin concentration, white cell and platelet count was observed. A bone marrow aspirate showed distinct recovery of normal hemopoiesis without residual leukemic cells. The patient has been staying in the complete remission for over 15 months with mepitiostane therapy (30 mg, daily). Androgen therapy, such as mepitiostane, appears to be effective in some patients with hypoplastic leukemia which does not indicate intensive chemotherapy.
...
PMID:[Complete remission by mepitiostane in hypoplastic leukemia]. 268 84

Twenty-three children with refractory or relapsed non-Hodgkin's lymphoma (NHL) received high-dose methotrexate (HD-MTX), and 9 received Ara-C by continuous intravenous infusion, as phase II studies. They all had previously received a protocol including vincristine, adriamycin, cyclophosphamide, IV push Ara-C, asparaginase, intrathecal MTX, and cranial irradiation, and had failed to respond or had relapsed. HD-MTX was given at the dose of 6 g/m2 or more with leucovorin rescue, Ara-C at the dose of 100 mg/m2/day by continuous infusion over 10 days. Among the 22 evaluable patients receiving HD-MTX, 10 responses (7 CR; 3 PR) were observed. Among the 9 patients receiving Ara-C, 4 responded (1 CR; 3 PR). Toxicity in those previously heavily treated patients was acceptable. These two drugs are now successfully included in childhood NHL treatment protocols.
...
PMID:High-dose methotrexate and continuous infusion Ara-C in children's non-Hodgkin's lymphoma: phase II studies and their use in further protocols. 315 14

Human DNA ligase was purified from different kinds of immunocompetent cells: thymocytes, normal and stimulated lymphocytes, blasts from ALL (Burkitt and non-T, non-B) and ANLL (M1, M2, and M5). Based upon the protocol for the treatment of these leukemias, the purified enzymes were assayed in the presence of routinely used combinations of antileukemic drugs. At the range of concentration tested (between 0.1 and 5 microM) some drugs taken separately were totally inactive on the enzyme from the different sources. For those being inhibitory, when used in combination their effect was always different from what was observed when the compound was tested alone. Some combinations were more effective in inhibiting the enzyme from leukemic than from normal cells (vincristine + cyclophosphamide + prednisone in ALL and rubidazone + Ara-C, Ara-C + m-AMSA, in ANLL). However, some combinations of drugs are without effect on ligase from leukemic cells at this dose range (vincristine + rubidazone + Ara-C + prednisone and adriamycin + asparaginase + Ara-C in ALL or etoposide + Ara-C, adriamycin + cyclophosphamide in ANLL). This is the first direct observation of the effect of cytostatic drugs on DNA ligase, a key enzyme of the DNA replication and repair process. The clinical consequences of these observations are discussed in an attempt to selectively inhibit replication, thereby division, of cancer cells.
...
PMID:Effects of clinical combinations of antileukemic drugs on DNA ligase from human thymocytes and normal, stimulated, or leukemic lymphocytes. 325 60


1 2 3 Next >>

---