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)

This article gives highlights of ongoing pediatric solid tumor and leukemia trials in the United States that use ifosfamide in combination with mesna. These trials are being carried out both by large cooperative groups and single institutions. Some role for ifosfamide with mesna in the front-line treatment of sarcomas is assured. Neurotoxicity, nephrotoxicity, and other unusual toxicities are discussed.
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PMID:Ongoing clinical studies of ifosfamide for pediatric cancer in the United States. 867 56

Telomerase activity and telomere length in mononuclear cells (MNCs) and granulocytes from peripheral blood (PB) and bone marrow (BM) specimens were studied in pediatric acute leukemia (ALL, n = 15; AML, n = 11) and pediatric solid tumor (ST) patients (n = 9) at diagnosis, during and after chemotherapy. In four ST patients, tumor tissue was also available. For comparative analysis, MNCs from healthy donors (n = 53) were analyzed. Telomerase was evaluated using a modified telomeric repeat amplification protocol (TRAP) assay, and telomere length by terminal restriction fragment (TRF) analysis. At diagnosis, high telomerase activity was detected in MNCs from all leukemia patients, which was similar to the activity from ST biopsy specimens. This exceeded by 10- to 20-fold the activity in PB MNCs from ST patients and healthy donors (P < 0.05). Granulocyte fractions lacked telomerase activity in all groups. BM MNCs in leukemia patients revealed a four-fold higher telomerase activity than PB (P = 0.005). After induction chemotherapy and response to treatment, telomerase activity decreased to borderline or undetectable levels in PB MNCs in leukemia (P < 0.01). Average telomeres in PB MNCs from pediatric patients were significantly longer (n = 25; 10.9 kbp) than telomeres in PB and BM MNCs from adult healthy donors (7.45 kbp) (P < 0.0001). At diagnosis, telomeres were shorter from BM compared to PB specimens in leukemia (P < 0.05), and two peak TRFs were observed corresponding to the malignant and normal cell clones. With the attainment of remission, the lower TRF peak, reflecting the leukemic population, was lost. In leukemia patients, mean TRFs increased on average 2.2 kbp after induction chemotherapy, but decreased thereafter on consolidation and maintenance chemotherapy (1 kbp). This was comparable to an average telomere loss of 1.2 kbp in PB specimens from ST patients after chemotherapy. In all patients, telomere loss in granulocytes as compared to MNCs was more pronounced with 1.8 vs 1 kbp, respectively (P = 0.014). Our results demonstrate that at diagnosis, telomerase was consistently and highly upregulated in BM and PB specimens in leukemia, decreased after induction therapy, and correlated with remission. BM specimens in leukemia had higher telomerase activity, probably due to the greater leukemic burden than in PB. Telomeres were significantly longer in children than in adults, but shortened as a consequence of chemotherapy with repeated cycles of hematopoietic regeneration. In acute leukemia, with the loss of the leukemic burden after induction chemotherapy, longer mean TRFs were found, a reflection of the repopulation with normal cells. Our findings suggest that telomerase activity may be useful in the management of childhood malignancies. The significance of telomere length shortening in pediatric patients undergoing chemotherapy and possible telomere regeneration after myelosuppressive treatment remain to be determined.
Leukemia 1998 Jan
PMID:Telomerase activity and telomere length in pediatric patients with malignancies undergoing chemotherapy. 943 16

Vorinostat, a histone deacetylase inhibitor, was evaluated against the in vitro and in vivo childhood solid tumor and leukemia models in the Pediatric Preclinical Testing Program (PPTP). In vitro testing was performed by the DIMSCAN cytotoxicity assay. In vivo, vorinostat was administered intraperitoneally to mice bearing xenografts. Vorinostat demonstrated 2-log cell growth inhibitory activity in vitro, but generally at concentrations not sustainable in the clinic. No objective responses were observed for any of the solid tumor or acute lymphoblastic leukemia xenografts. Preclinical studies with appropriate drug combinations may provide direction for further clinical evaluations of vorinostat against selected pediatric cancers.
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PMID:Initial testing (stage 1) of vorinostat (SAHA) by the pediatric preclinical testing program. 1941 47