UMLS:C0023418 - FACTA Search

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)

The records of 415 patients who received allogeneic marrow transplants for acute leukemia were reviewed to assess the risk of central nervous system (CNS) relapse and leukoencephalopathy after marrow transplantation. The Kaplan-Meier estimates of the probability of CNS relapse posttransplant were 13% for patients with acute lymphoblastic leukemia (ALL) and 2% for patients with acute nonlymphoblastic leukemia (ANL). Previous CNS disease was significantly correlated with an increased risk of CNS relapse in patients transplanted for ALL but not for ANL. In contrast, bone marrow involvement with leukemia at the time of transplant was associated with an increased risk of CNS relapse in patients with ANL but not in patients with ALL. Seventy-one patients with ALL did not receive posttransplant intrathecal methotrexate (IT-MTX) and 127 did. The probability of CNS relapse in these two groups was 38% and 7%, respectively (P less than .02). This protective benefit from IT-MTX was present in patients both with and without a history of CNS involvement or marrow involvement at the time of transplant. In patients with ANL, 116 patients did not receive posttransplant IT-MTX and 101 patients did, but no protection from CNS relapse was observed from IT-MTX irrespective of a patient's previous CNS history or marrow status at the time of transplant. Leukoencephalopathy was seen exclusively in patients who had received radiation and/or intrathecal chemotherapy to the CNS before preparation for marrow transplantation and posttransplant IT-MTX. In such patients the risk of leukoencephalopathy was 7%. From our data, it appears that posttransplant IT-MTX is a significant benefit for ALL patients in preventing CNS relapse after marrow transplantation. A similar benefit from posttransplant IT-MTX for ANL patients cannot be established from this study. In both groups, increasing total CNS therapy was associated with an increasing risk of leukoencephalopathy.
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PMID:The risks of central nervous system relapse and leukoencephalopathy in patients receiving marrow transplants for acute leukemia. 351 66

In Essen 121 bone marrow transplantations were carried out. The indications were severe aplastic anemia (n = 18), acute leukemia in relapse (n = 20), acute leukemia in remission (n = 46) or chronic myeloid leukemia (n = 37). The conditioning regimen consisted of cyclophosphamide or the combination of cyclophosphamide and total body irradiation. All patients were treated under strict gnotobiotic care. To mitigate the risk of CMV infections intravenous CMV-hyperimmunoglobulin and CMV-negative blood products have been applied routinely since two years. MTX was used as prophylaxis against GVH-disease. In case of severe aplastic anemia 13 patients (72%) are still alive with a median observation time of 24 months. In the prognostically unfavourable group of acute leukemia in relapse only one patient showed long term survival. In this patient leukemic relapse occurred six years after transplantation. The survival rate of AML patients grafted during the first remission is 55% (15/27) with a median observation time of 40 months. For patients grafted in first or consecutive remission of ALL the survival rate is 42% (5/12) with a maximal observation time of 29 months. Out of 37 patients grafted because of CML, eight were in an advanced stage of the disease. 13 patients are still alive, the maximal observation time is 37 months. The overall incidence of GVHD in patients at risk was 28% in aplastic anemia, 26% in AML, 9% in ALL and 63% in CML. In aplastic anemia no patient developed an interstitial pneumonia. In leukemia the risk of fatal interstitial pneumonia was 34%.
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PMID:Bone marrow transplantation in severe aplastic anemia and acute or chronic leukemia. 351 96

Dihydrofolate reductase, purified to homogeneity from a subline of L1210 murine leukemia cells resistant to 10(-6) M Methotrexate, was resolved into two principal forms (1 and 2) by isoelectric focusing. These forms had pI values of 7.4 and 8.2, respectively; both stained for protein and catalytic activity. Form 1 was a single component, comprising ca. 10% of the total protein, but multiple components of 2 were observed by narrowing the pH range in the electrophoretic procedure. Urea-denatured enzyme exhibited two bands of approximately equal intensity upon isoelectric focusing. These results were interpreted to mean that the enzyme consists of a set of conformationally different forms, arising from two primary structures. Inhibition of the native enzyme by Methotrexate was polyphasic, and appreciable activity remained when the drug was present at an equimolar concentration. Various agents (KCl, H+, urea, and SH-modifiers), known to "activate" dihydrofolate reductases, produced a monophasic, stoichiometric inhibition. Activating agents appear to induce a more open (and labile) conformation of the enzyme. This leads to increased affinity for MTX accompanied, in some instances, by increased catalytic activity.
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PMID:L1210 dihydrofolate reductase: activation and enhancement of methotrexate sensitivity. 383 18

A new regimen for prevention of acute graft-versus-host disease (GvHD)--OKT3 (murine monoclonal anti-pan-T antibody), prednisone and methotrexate (OKT3-pred-MTX)--was compared with the Minnesota standard regimen--antithymocyte globulin, prednisone and methotrexate (ATG-pred-MTX)--for adverse effects, effect on incidence of acute GvHD, and survival at 1 year post-transplant. Twenty patients (aged 25 +/- 9 years) had bone-marrow transplantation (BMT) from their HLA-MLC identical sibling donors for treatment of aplastic anaemia (four), acute leukaemia in remission (13) or chronic myelogenous leukaemia (three). These 20 patients received (OKT3-pred-MTX) on days 8-22 post-transplant. Results of this group are compared to those of 19 concurrent patients (aged 26 +/- 12 years) who received ATG-pred-MTX on days 8-22 post-transplant. On the first day of treatment, 20/20 OKT3 patients and 18/19 ATG patients were febrile. Within 24 h of the first dose of OKT3, 6/20 patients experienced dyspnoea or chest pain and 3/20 patients developed diarrhoea. No further adverse effects were seen after the second dose of OKT3 and no late adverse effects were attributed to this drug. Time to engraftment (means 25 d) was not statistically significantly different in the two prophylactic groups. Acute GvHD was diagnosed in 14 of 20 patients who received OKT3-pred-MTX and in eight of 19 patients who received ATG-pred-MTX (P = 0.06). The incidence of hepatic or gastrointestinal GVHD (greater than or equal to grade 2) was similar in the two groups: 4/20 OKT3-pred-MTX, 6/19 ATG-pred-MTX. Characteristics of post-transplant infections were also similar for the two prophylactic groups. Survival at 1 year post-transplant was 65% for patients who received OKT3 and 44% for patients who received ATG (P = 0.13). The use of OKT3 with prednisone and methotrexate is relatively safe and is associated with a similar incidence of moderate-severe acute GvHD to that experienced in the use of ATG with prednisone and methotrexate.
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PMID:Graft-versus-host disease prophylaxis with anti-T-cell monoclonal antibody OKT3, prednisone and methotrexate in allogeneic bone-marrow transplantation. 389 Sep 26

Combination chemotherapy using the water-soluble nitrosourea MCNU with various anti-cancer agents was studied using L1210 leukemia and P388 leukemia. In titration experiments MCNU showed remarkable antitumor effects at doses from 5 mg/kg to 80 mg/kg, producing numbers of 60-day survivors with L1210 leukemia. In L1210 leukemia, respective combinations of MCNU with the antimetabolites, MTX, 6-MP, 6-TG, MCNU, 5-FU and Cyclo-C showed enhanced antitumor effects. MCNU combined with each of ADR, MMC and CPM also showed marked anti-tumor effects with 60-day survivors. In P388 leukemia MCNU combined with each of ADR, MMC, VDS and CPM produced strong anti-tumor effects with numbers of 60-day survivors. In the results of these combinations, especially the combinations of MCNU + 5-FU in L1210 leukemia and MCNU + CPM in both L1210 and P388 leukemia, a significant increase in mean survival time was achieved. These combinations also produced many 60-day survivors which were considered to be due to the synergistic antitumor effects of the combined drugs.
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PMID:[Effects of combination chemotherapy of MCNU with various anti-cancer agents]. 391 6

PTT.119 [p-F-Phe-m-bis-(2-chloroethyl)amino-L-Phe-Met ethoxy HCl], a new synthetic tripeptide, was highly effective against the L-phenylalanine mustard (L-PAM) resistant (L1210/L-PAM and P388/L-PAM) tumor lines, as well as the sensitive L1210 leukemia. Cytolytic activity of PTT.119 against all three leukemias was significantly greater than equimolar doses of L-PAM. These in vitro results paralleled the significant increases in mean survival times of hosts and, in some cases, abrogations of tumor formation observed in the in vivo bioassays of PTT.119-treated L1210 and L1210/L-PAM cells. Dose-response studies failed to demonstrate cross-resistance to the tripeptide by L-PAM resistant cells. Doses of PTT.119 required to reduce the viable fraction by 50% (tissue culture dose 50, TCD50) or 100% (TCD100) were 1.3- to 3-fold lower for the L-PAM resistant cells than for the L1210 leukemia. In comparison, L-PAM was unable to completely eliminate cell survival; 0.2 to 3% of the cells in all three leukemias remained viable even at doses of 75 and 163 microM. In similar studies, L1210 leukemia cells made resistant to methotrexate (L1210 MTX) and cisplatin (L1210DDP) were also completely susceptible to PTT.119; TCD50 values of the two resistant lines were 1.94 microM for L1210 MTX and 0.525 microM for L1210DDP compared to 2.38 microM for the susceptible parent L1210S leukemia. Continuous low-dose PTT.119 treatment of MJY-alpha mammary tumor cells for 8 months and exposure of L1210 leukemia to escalating levels of tripeptide for over 100 passages failed to select or induce drug-resistant phenotypes in either cell line. PTT.119 appears to be a poor mutagen and is unlikely to readily increase the probability of drug-resistant mutants in the tumor cell populations.
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PMID:PTT.119, p-F-Phe-m-bis-(2-chloroethyl)amino-L-Phe-Met ethoxy HCl, a new chemotherapeutic agent active against drug-resistant tumor cell lines. 404 Mar 66

Dihydrofolate reductase, purified to homogeneity (as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis), from a subline of L1210 murine leukemia cells resistant to 10(-6) M methotrexate, was resolved into two principal forms (1 and 2) by polyacrylamide gel electrophoresis at pH 8.3 or isoelectric focusing. In the latter procedure, these forms had pI values of 7.4 and 8.2, respectively; both stained for protein and catalytic activity. Form 1 appears to be a single component, comprising ca. 10% of the total protein and at least 20% of the total catalytic activity. It is also more sensitive to inhibition by MTX, more heat-stable, and less susceptible to activation than form 2. Multiple components of 2 were observed by narrowing the pH range in isoelectric focusing, and further resolution was achieved by urea denaturation. Substrate and inhibitor complexes of 1 and 2, differentiated by polyacrylamide gel electrophoresis or isoelectric focusing, provided information about the ability of the enzyme to undergo conformational changes. Interconversion of 1 with one of the components of 2 may also involve conformational isomerism. These conclusions are consistent with the well-known ability of eukaryotic dihydrofolate reductases to exhibit increased catalytic activity (attributed to transformations to more open conformations) when treated with salts, chaotropes, or cysteine-modifying agents. Treatment of the L1210/R6 enzyme preparation with one of these activating agents, 5,5'-dithiobis(2-nitrobenzoic acid), derivatized both 1 and 2 (changing their pI values to 7.3 and 6.9, respectively) and altered the enzyme such that stoichiometric inhibition for MTX was observed.
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PMID:Polymorphism of dihydrofolate reductase from a methotrexate-resistant subline of L1210 cells. 407 99

The Children's Cancer Study Group has organised two therapeutic clinical trials designed to evaluate the efficacy of various types and doses of CNS prophylaxis in the treatment of childhood acute lymphoblastic leukaemia. Of 478 previously untreated patients who subsequently achieved an initial marrow remission, 299 were randomised to receive 2400 rad craniospinal radiation therapy (RT) or 2400 rad cranial RT plus intrathecal methotrexate (i.t. MTX) while the remaining 179 patients were randomised between the same two regimens using a radiation dose of 1800 rad. All patients received identical induction and maintenance chemotherapy. Comparison of the two studies indicated that reduction of the dose of CNS radiation from 2400 rad to 1800 rad did not result in a significant increase in the frequency of CNS relapse, bone marrow relapse, or death. Moreover, no significant differences were observed when analyses were done within prognostic risk groups. Randomised trials with RT doses lower than 1800 rad or with i.t. chemotherapy alone should be considered to determine the most effective and least toxic forms of CNS prophylaxis.
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PMID:Presymptomatic central nervous system therapy in previously untreated childhood acute lymphoblastic leukaemia: comparison of 1800 rad and 2400 rad. A report for Children's Cancer Study Group. 611 90

Chain-extended analogues of methotrexate were synthesized by condensation of 4-amino-4-deoxy-N10-methylpteroic acid with esters of L-alpha-aminoadipic, L-alpha-aminopimelic, and L-alpha-aminosuberic acids, followed by ester hydrolysis with acid or base. Coupling was accomplished in up to 85% yield by the use of the peptide bond forming reagent diethyl phosphorocyanidate at room temperature. The products were found to bind bacterial (Lactobacillus casei) and mammalian (L1210 mouse leukemia) dihydrofolate reductase with an affinity comparable to methotrexate and were also equitoxic to L1210 cells in culture. Cytotoxicity increased up to 3-fold as the number of CH2 groups in the amino acid side chain was extended from two to five. The alpha-aminoadipate and alpha-aminopimelate analogues were poor substrates for carboxypeptidase G1, confirming that this enzyme has a strict requirement for a C-terminal L-glutamic acid residue. The in vivo antitumor activity of the chain-extended analogues against L1210 leukemia in mice was comparable to that of the parent drug on the qd X 9 schedule, but higher doses were required to achieve the same increase in survival. The results were consistent with findings, reported separately, that these compounds are poor substrates for folate polyglutamate synthetase and therefore would not be expected to form gamma-polyglutamates once they enter a cell. This distinctive property has potential therapeutic implications for the treatment of certain MTX-resistant tumors whose resistance may be associated with a lower than normal capacity to form gamma-polyglutamates in comparison with proliferative tissues such as intestinal mucosa or marrow.
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PMID:Methotrexate analogues. 20. Replacement of glutamate by longer-chain amino diacids: effects on dihydrofolate reductase inhibition, cytotoxicity, and in vivo antitumor activity. 613 80

7-Hydroxymethotrexate, an important metabolite of methotrexate, is a substrate for folylpolyglutamate synthetase (FPGS) isolated from rat liver and several human leukemia cell lines. The substrate activity it displays over a wide range of concentrations (0-200 microM) is nearly equivalent to that of methotrexate. The 7-hydroxy derivative of dichloromethotrexate is also a substrate for FPGS. The pattern of polyglutamate products synthesized by rat liver FPGS was nearly identical with both 7-hydroxymethotrexate and methotrexate. In addition, conversion of MTX polyglutamates to the corresponding 7-hydroxy compounds was demonstrated using partially purified rabbit liver aldehyde oxidase. The rate of conversion was concentration dependent, and the relative rate decreased as the MTX polyglutamate chain length increased. We propose that 7-hydroxymethotrexate polyglutamates may be formed by initial hydroxylation of methotrexate and subsequent polyglutamate formation or by direct hydroxylation of methotrexate polyglutamates. It was further shown that the relative substrate activity of folate analogs for folylpolyglutamate synthetase is dependent on the source of the enzyme.
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PMID:Enzymatic synthesis of polyglutamate derivatives of 7-hydroxymethotrexate. 620 Nov 78

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