1,443 research outputs found
Features of Pavement Damage due to Hyogo-ken Nanbu Earthquake
Translocation of the LYL1 oncogene are rare in T-cell acute lymphoblastic leukemia, whereas the homologous TAL1 gene is rearranged in approximately 20% of patients. Previous gene-expression studies have identified an immature T-cell acute lymphoblastic leukemia subgroup with high LYL1 expression in the absence of chromosomal aberrations. Molecular characterization of a t(7;19)(q34;p13) in a pediatric T-cell acute lymphoblastic leukemia patient led to the identification of a translocation between the TRB@ and LYL1 loci. Similar to incidental T-cell acute lymphoblastic leukemia cases with synergistic, double translocations affecting TAL1/2 and LMO1/2 oncogenes, this LYL1-translocated patient also had an LMO2 rearrangement pointing to onco-genic cooperation between LYL1 and LMO2. In hierarchical cluster analyses based on gene-expression data, this sample consi
Allergic-like reactions to asparaginase: Atypical allergies without asparaginase inactivation
Background: Asparaginase is an important component of pediatric acute lymphoblastic leukemia (ALL) therapy. Unfortunately, this treatment is hampered by hypersensitivity reactions. In general, allergies – regardless of severity – cause complete inactivation of the drug. However, we report atypical allergic reactions without inactivation of asparaginase, here called allergic-like reactions. Procedure: Patients with an allergic-like reaction, who were treated according to the Dutch Childhood Oncology Group ALL-11 or the CoALL 08–09 protocol, were described. The reactions were identified by continual measurement of asparaginase activity levels. Characteristics, including timing of occurrence, symptoms, grade, and the presence of antiasparaginase antibodies, were compared to those of real allergies. Results: Fourteen allergic-like reactions occurred in nine patients. Five reactions were to PEGasparaginase and nine to Erwinia asparaginase. Allergic-like reactions occurred relatively late after the start of infusion compared to real allergies. Antibodies were absent in all but one patient with an allergic-like reaction, while they were detected in all patients with a real allergy. Symptoms and grade did not differ between the groups. Asparaginase was continued with the same formulation in six patients of whom four finished treatment with adequate activity levels. Conclusions: In conclusion, allergic-like reactions occur relatively late after the start of infusion and without antibodies. Despite these clinical differences, allergic-like reactions can only be distinguished from real allergies by continually measuring asparaginase activity levels. If clinically tolerated, formulations should not be switched in case of allergic-like reactions. Moreover, failure to recognize these reactions may lead to a less favorable prognosis if asparaginase therapy is terminated unnecessarily
Resistance to different classes of drugs is associated with impaired apoptosis in childhood acute lymphoblastic leukemia
Resistance of leukemic cells to chemotherapeutic agents is associated with
an unfavorable outcome in pediatric acute lymphoblastic leukemia (ALL). To
investigate the underlying mechanisms of cellular drug resistance, the
activation of various apoptotic parameters in leukemic cells from 50
children with ALL was studied after in vitro exposure with 4 important
drugs in ALL therapy (prednisolone, vincristine, l-asparaginase, and
daunorubicin). Exposure to each drug resulted in early induction of
phosphatidylserine (PS) externalization and mitochondrial transmembrane
(Deltapsim) depolarization followed by caspase-3 activation and
poly(ADP-ribose) polymerase (PARP) inactivation in the majority of
patients. For all 4 drugs, a significant inverse correlation was found
between cellular drug resistance and (1) the percentage of cells with PS
externalization (<.001 < P <.008) and (2) the percentage of cells with
Deltapsim depolarization (.002 < P <.02). However, the percentage of cells
with caspase-3 activation and the percentage of cells with PARP
inactivation showed a significant inverse correlation with cellular
resistance for prednisolone (P =.001; P =.001) and l-asparaginase (P =.01;
P =.001) only. This suggests that caspase-3 activation and PARP
inactivation are not essential for vincristine- and daunorubicin-induced
apoptosis. In conclusion, resistance to 4 unrelated drugs is associated
with defect(s) upstream or at the level of PS externalization and
Deltapsim depolarization. This leads to decreased activation of apoptotic
parameters in resistant cases of pediatric AL
Biological background of pediatric medulloblastoma and ependymoma: A review from a translational research perspective
Survival rates of pediatric brain tumor patients have significantly improved over the years due to developments in diagnostic techniques, neurosurgery, chemotherapy, radiotherapy, and supportive care. However, brain tumors are still an important cause of cancer-related deaths in children. Prognosis is still highly dependent on clinical characteristics, such as the age of the patient, tumor type, stage, and localization, but increased knowledge about the genetic and biological features of these tumors is being obtained and might be useful to further improve outcome for these patients. It has become clear that the deregulation of signaling pathways essential in brain development, for example, sonic hedgehog (SHH), Wnt, and Notch pathways, plays an important role in pathogenesis and biological behavior, especially for medulloblastomas. More recently, data have become available about the cells of origin of brain tumors and the possible existence of brain tumor stem cells. Newly developed array-based techniques for studying gene expression, protein expression, copy number aberrations, and epigenetic events have led to the identification of other potentially important biological abnormalities in pediatric medulloblastomas and ependymomas. Copyright 2008 by the Society for Neuro-Oncology
Impaired dexamethasone-related increase of anticoagulants is associated with the development of osteonecrosis in childhood acute lymphoblastic leukemia
Coagulation alterations may be involved in osteonecrosis in childhood acute lymphoblastic leukemia. Retrospectively, we evaluated the available coagulation parameters at diagnosis and during induction treatment of 161 acute lymphoblastic leukemia patients: 24 with symptomatic osteonecrosis (median age: 13.8 years, range 4.0-17.2) and 137 without osteonecrosis (median age: 4.9 years, range 1.0-16.7). Coagulation parameters of both groups were similar at diagnosis. After four weeks of treatment including dexamethasone, levels of antithrombin and protein S were significantly less in osteonecrosis-positive than in osteonecrosis-negative patients. Subsequently, after four doses of asparaginase and tapering dexamethasone, these coagulation parameters equally decreased in both groups. Consequently, nadirs of antithrombin and protein S were significantly lower in osteonecrosis-positive than in osteonecrosis- negative patients, even reaching levels below lower normal limits in the osteonecrosis-positive group. A reduced dexamethasone related increase of antithrombin and protein S, and subsequent decline below normal levels after introduction of asparaginase, may result in a hypercoagulable state, contributing to development of symptomatic osteonecrosis
Decreased PARP and procaspase-2 protein levels are associated with cellular drug resistance in childhood acute lymphoblastic leukemia
Drug resistance in childhood acute lymphoblastic leukemia (ALL) and acute
myeloid leukemia (AML) is associated with impaired ability to induce
apoptosis. To elucidate causes of apoptotic defects, we studied the
protein expression of Apaf-1, procaspases-2, -3, -6, -7, -8, -10, and
poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) in cells from
children with acute lymphoblastic leukemia (ALL; n = 43) and acute myeloid
leukemia (AML; n = 10). PARP expression was present in all B-lineage
samples, but absent in 4 of 15 T-lineage ALL samples and 3 of 10 AML
cases, which was not caused by genomic deletions. PARP expression was a
median 7-fold lower in T-lineage ALL (P < .001) and 10-fold lower in AML
(P < .001) compared with B-lineage ALL. PARP expression was 4-fold lower
in prednisolone, vincristine and L-asparaginase (PVA)-resistant compared
with PVA-sensitive ALL patients (P < .001). Procaspase-2 expression was
3-fold lower in T-lineage ALL (P = .022) and AML (P = .014) compared with
B-lineage ALL. In addition, procaspase-2 expression was 2-fold lower in
PVA-resistant compared to PVA-sensitive ALL patients (P = .042). No
relation between apoptotic protease-activating factor 1 (Apaf-1),
procaspases-3, -6, -7, -8, -10, and drug resistance was found. In
conclusion, low baseline expression of PARP and procaspase-2 is related to
cellular drug resistance in childhood acute lymphoblastic leukemia
High PDGFRA expression does not serve as an effective therapeutic target in ERG-deleted b-cell precursor acute lymphoblastic leukemia
Cost-analysis of treatment of childhood acute lymphoblastic leukemia with asparaginase preparations: The impact of expensive chemotherapy
__Abstract__
Asparaginase is an expensive drug, but important in childhood acute lymphoblastic leukemia. In order to compare costs of PEGasparaginase, Erwinia asparaginase and native E. coli asparaginase, we performed a cost-analysis in the Dutch Childhood Oncology Group ALL-10 medium-risk group intensification protocol. Treatment costs were calculated based on patient level data of 84 subjects, and were related to the occurrence of allergy to PEGasparaginase. Simultaneously, decision tree and sensitivity analyses were conducted. The total costs of the intensification course of 30 weeks were 113,558) in case of allergy (n=20) necessitating a switch to Erwinia asparaginase. Simulated scenarios (decision tree analysis) using native E. coli asparaginase in intensification showed that the costs of PEGasparaginase were equal to those of native E. coli asparaginase. Also after sensitivity analyses, the costs for PEGasparaginase were equal to those of na
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