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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pharmacokinetics of daunorubicin and doxorubicin were studied in plasma and leukemic cells from 16 patients with acute nonlymphoblastic leukemia during 19 courses of treatment with the unconjugated or DNA-conjugated drugs. Daunorubicin and doxorubicin are high-clearance drugs with very high apparent volumes of distribution, indicating a pronounced tissue affinity. This was more pronounced in the case of doxorubicin and may explain the reduced cardiotoxicity of the DNA-complexes. Daunorubicin reached higher intracellular peak concentrations than doxorubicin, but the latter drug was retained much longer. The cell/plasma concentration ratio was higher for daunorubicin than for its reduced metabolite daunorubicinol. No doxorubicinol was found intracellularly. The observed differences in cellular pharmacokinetics between daunorubicin and doxorubicin may explain the difference between the clinical activity spectras of these two drugs. DNA-conjugation did not markedly modify the uptake of daunorubicin in the leukemic cells, whereas the mean intracellular accumulation of doxorubicin was 60% higher when the drug was administered as a DNA-conjugate. This may enhance the selectivity of doxorubicin in the treatment of acute leukemia.
Ther Drug Monit 1989
PMID:Pharmacokinetics of daunorubicin and doxorubicin in plasma and leukemic cells from patients with acute nonlymphoblastic leukemia. 271 19

A pharmacokinetic study was performed in 13 adult patients with acute nonlymphoblastic leukemia to compare two formulations of 4'-(9-acridinylamino)-methanesulphone-m-ansidide (AMSA): the original formulation, AMSA-NCL, and a water-soluble lyophilized formulation, AMSA-lactate (Bristol Myers, Syracuse, N.Y. USA). Initially, the patients received either AMSA-NCL or AMSA-lactate, 75-90 mg/m2 daily, for 3-7 days as a 1-h infusion. Eight patients subsequently crossed over to receive the other formulation. Plasma samples for drug determination were collected during the first 3 days. A new method for determination of AMSA is described. Acidified plasma samples containing an internal standard were extracted with hexane, then made alkaline, whereafter, AMSA was extracted with ethylacetate. Extracts were reconstituted in absolute ethanol and analyzed by high-pressure liquid chromatography (HPLC) using a reverse-phase C-18 column and UV detection at 254 nm. There were no clear differences in clinical effects and toxicity between the two formulations. Patients with the highest total area under the drug concentration-versus-time curves (AUCs) for plasma concentrations versus time had significantly lower nadir for white blood cell count, suggesting a relation between plasma levels and bone marrow toxicity for AMSA. The pharmacokinetics showed a biphasic elimination for both formulations. The mean terminal elimination half-life of AMSA-NCL and AMSA-lactate was 7.1 and 6.3 h, respectively, and the mean volume of distribution was 105 and 99 L/m2, respectively. No significant differences in the pharmacokinetics comparing days 1 and 3 were seen.(ABSTRACT TRUNCATED AT 250 WORDS)
Ther Drug Monit 1987 Sep
PMID:Comparison of the pharmacokinetics of AMSA and AMSA-lactate in patients with acute nonlymphoblastic leukemia. 367 68

Pediatric patients with leukemia, other malignancies, and rheumatological disease receive methotrexate chronically. Because of the documented correlation between methotrexate levels of compliance and clinical outcome, it is conceivable to verify appropriate systemic exposure to the drug. Saliva sampling may be of potential interest, especially in children, in whom blood sampling is ethically limited. Our study shows poor correlation between serum total/free methotrexate concentrations and saliva levels, precluding the clinical use of this test.
Ther Drug Monit 1995 Jun
PMID:Evaluation of therapeutic drug monitoring of methotrexate in saliva of children with rheumatic diseases. 762 20

The increasing insights into the pharmacokinetics and the metabolism of arabinoside C (AraC) have improved the rationale for its application in leukemia therapy and have led to a pharmacologically directed design of antileukemic treatment. The current study aims at adding to this approach by detecting differences in the intracellular metabolism of AraC 5'-triphosphate (AraCTP) between leukemic and normal mononuclear blood cells. Measurements of intracellular AraCTP levels were complemented by determinations of plasma AraC and arabinoside uridine (AraU) concentrations and were performed in 26 patients with acute myeloid leukemia (AML) who were undergoing combination therapy, including high-dose (1.0 or 3.0 g/m2 x 2/day) AraC. Plasma AraC concentrations showed a linear relationship to the applied AraC dose but did not correlate with intracellular AraCTP levels. Substantial differences in AraCTP retention times were revealed, during 3-h infusions of either 1.0 or 3.0 g/m2 AraC in leukemic blasts from 10 patients with t1/2 values of 1.60-7.63 h (median, 2.42 h). In addition, AraCTP levels declined in only one patient by > 10% within the first hour after the end of therapy and remained constant or even increased up to 1.5-fold during a posttreatment period of 1-2.5 h in the other nine cases. In contrast, AraCTP retention times were relatively uniform in normal mononuclear blood cells from 11 patients, with t1/2 values of 3.34-5.29 h (median, 3.85 h). More importantly, AraCTP levels dropped by > 10% within the first hour after the end of the high-dose AraC infusion in eight of 11 cases. A posttherapeutic increase of > 10% was not observed in any patient. These differences in AraCTP pharmacokinetics between leukemic and normal blood cells provided the basis for a modified timing of AraC administration with the aim of selectively maintaining cytotoxic AraCTP levels in leukemic blasts while allowing an intermittent drop of AraCTP levels in normal cells. This modification may result in higher antileukemic activity without increasing the damaging effect on normal cells and may, thus, improve the therapeutic index for AraC.
Ther Drug Monit 1996 Aug
PMID:Optimizing therapy for acute myeloid leukemia based on differences in intracellular metabolism of cytosine arabinoside between leukemic blasts and normal mononuclear blood cells. 885 48

Childhood acute lymphoblastic leukemia (ALL) has long served as a model of disseminated cancer that can be cured with chemotherapy. Although pharmacokinetic variability has been shown to influence the efficacy of ALL chemotherapy, the usefulness of conventional pharmacokinetic measures to predict responses to individual chemotherapeutic agents can be confounded in the context of multiagent chemotherapy. This has led to the concomitant use of pharmacodynamic endpoints to identify patients who exhibit a poor initial response to therapy or whose residual disease has a persistence that predicts a poor prognosis unless therapy is changed. To this end, the initial reduction of leukemia cells in peripheral blood or in bone marrow and the detection of minimal residual disease by immunologic or polymerase chain reaction-based methods have shown promise as pharmacodynamic endpoints to identify patients who are at high risk for relapse if therapy remains unchanged. Prospective clinical trials are needed to determine the clinical usefulness of pharmacodynamic monitoring and to define more precisely the integration of pharmacokinetic and pharmacodynamic monitoring to optimize the treatment of childhood ALL.
Ther Drug Monit 1998 Oct
PMID:Pharmacodynamic monitoring of cancer chemotherapy: childhood acute lymphoblastic leukemia as a model. 978 Jan 17

This study examined the role of thiopurine methyltransferase (TPMT) polymorphism in the metabolism and clinical effects of azathioprine and 6-mercaptopurine in the treatment of inflammatory bowel disease and childhood leukemia. The current hypothesis is that the cytotoxic effects of thiopurines are caused by the incorporation of thioguanine nucleotides into DNA. In this context, S-methylation catalyzed by TPMT can be regarded as a competing metabolic pathway. The authors assayed the TPMT activity in red blood cells from 122 patients treated with azathioprine or 6-mercaptopurine (83 adults with inflammatory bowel disease and 39 children with acute lymphoblastic leukemia) and in 290 untreated controls (219 adult blood donors and 71 children). The concentrations of thioguanine nucleotides and methylthioinosine monophosphate were also assayed in red blood cells from the patients. The TPMT activity and the concentrations of methylthioinosine monophosphate and thioguanine nucleotides were higher in children than in adults. All children but no adult patient received concomitant methotrexate. Interaction between methotrexate and 6-mercaptopurine has been described, and may explain the results. Low TPMT activity in adult patients with inflammatory bowel disease correlated to an increased incidence of adverse drug reactions. However, there was no correlation between TPMT activity and the red blood cell concentrations of methylthioinosine monophosphate or thioguanine nucleotides, or between the concentrations of these metabolites and the occurrence of adverse effects. The results show that the role of thiopurine metabolism for drug effects is complex.
Ther Drug Monit 2002 Jun
PMID:Differences between children and adults in thiopurine methyltransferase activity and metabolite formation during thiopurine therapy: possible role of concomitant methotrexate. 1202 25

High-dose chemotherapy followed by allogenic stem cell transplantation has been extensively used for the treatment of patients with hematological malignancies. Unfortunately, this life saving procedure is limited to a subset of patients who are in good medical condition due to the increased risk of regimen-related toxicity and graft-versus-host disease that occur with increasing age and poor performance status. On the other hand, it became apparent that the curative potential of transplantation was not solely due to the conditioning regimen but also to the graft-versus-leukemia effect mediated by alloreactive donor T cells. These observations led to the development of new transplant strategies using less intensive preparative regimens that would allow donor cell engraftment without the toxicity of myeloablative conditioning as a method of exploiting a graft-versus-malignancy effect in patients ineligible for conventional marrow grafts. Although follow-up is relatively short, preliminary results are encouraging and demonstrate the feasibility of non-myeloablative transplants in patients with heterogeneous diseases and disease status who Current challenges include defining the optimal regimen to promote full donor engraftment and the malignancies susceptible to this approach. The present review summarizes the most recent results obtained in this attractive field.
Med Sci Monit 2002 Oct
PMID:Allogenic stem cell transplantation following non-myeloablative conditioning regimens as adoptive immunotherapy in patients with hematological malignancies. 1238 32

A health hazard, specifically the leukaemia risk, is evaluated from different sources of benzene exposure with relation to a population living in an urban area of Italy. The population exposure is calculated for a reference year by sex and lifestyle, with respect to smokers and non smokers. Potential health risk is therefore quantified by means of mathematical models and the relative significance of the different sources is described. The results of the analysis are useful for the identification of appropriate risk reduction strategies to minimize exposure, in particular when resulting from lifestyle and personal activities.
Environ Monit Assess 2002 Dec
PMID:Assessing health risk from benzene pollution in an urban area. 1244 21

Infectious complications constitute the second most common cause of mortality and a main cause of morbidity in beta-thalassemia. Besides the high risk of blood-borne infections associated with multiple transfusions, the increased susceptibility of these patients to infectious diseases has been attributed to a coexistent immune deficiency. Immune abnormalities have also been held responsible for the frequent occurrence of malignancies in beta-thalassemia, especially leukemia and lymphomas. Recent studies on immune competence in beta-thalassemia have revealed numerous quantitative and functional defects, involving T and B lymphocytes, immunoglobulin production, neutrophils and macrophages, chemotaxis, and phagocytosis, as well as the complement system. Regarding pathogenesis, iron overload, a primary complication of both thalassemia itself and transfusion therapy, is thought to be the main precipitating mechanism, due to the important immunoregulatory properties of iron and its binding proteins; iron excess may derange the immune balance in favor of the growth of infectious organisms. Other factors include multiple transfusions, associated with constant allo-antigenic stimulation, as well as with transmission of immunosuppressive viruses; splenectomy, resulting in increased susceptibility to infections by encapsulated bacteria and to immune system modifications; low levels of zinc, another immune regulator; iron chelation therapy, which predisposes to serious infections by yersinia species; and the circulation of abnormal native thalassemic erythrocytes, forming another permanent immune stimulus. Thus surveillance for infections in patients with beta-thalassemia is crucial, while further studies are warranted on immune function abnormalities and the implicated mechanisms.
Med Sci Monit 2003 Jan
PMID:Pathogenetic aspects of immune deficiency associated with beta-thalassemia. 1255 54

With the recent focus on environmental problems, increasing awareness of the harmful effects of industrial and agricultural pollution has created a demand for progressively more sophisticated pollutant and toxicity detection methods. Using Aspergillus nidulans strains this work presents a new short term-test that, most importantly, enables the rapid and inexpensive detection of volatile pollutants that induce genotoxic/carcinogenic effects in animals. The main aim is to contribute to environmental health protection, and special attention is directed to monitoring the hazard posed by benzene (as a carcinogenic agent model) mainly because its ubiquitous presence often leads to severe noxious effects in humans among whom increased rates of human leukemia have been reported. To evaluate even the submutagenic effects of benzene fumes, two Aspergillus nidulans diploid strains, heterozygous for several auxotrophic mutations, were used. The DNA lesions produced stimulate mitotic recombination and homozygotization of auxotrophic recessive mutations. Conidial exposure to a saturated atmosphere of benzene fumes for 20 s was enough to increase the mitotic recombination frequencies significantly. Genetic analyses of treated diploids evidenced alterations related to mitotic recombination frequencies, gene expression, and allelic segregation rates. Altogether they reflect the potential of benzene to induce alterations in the fungal DNA, and albeit indirectly, they also respond for the genotoxic/carcinogenic harmful side effects widely connected to benzene. This is the first description of a sensitive, rapid and inexpensive test able to detect the submutagenic dose effects of volatile environmental compounds. In addition, despite concentrating on benzene the same test can be applied to many other pollutants, volatile or not. Additionally, the test can also be used to detect the antigenotoxic properties of foods and drugs.
J Environ Monit 2005 Jun
PMID:A short-term test adapted to detect the genotoxic effects of environmental volatile pollutants (benzene fumes) using the filamentous fungus Aspergillus nidulans. 1593 21


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