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Biomedical subjects

D Mahoney

Publications and source records attributed to D Mahoney.

At least 19 recordsLinked to original sources
PubMed1994

Intensive intravenous methotrexate and mercaptopurine treatment of higher-risk non-T, non-B acute lymphocytic leukemia: A Pediatric Oncology Group study.

PURPOSE: To determine the potential efficacy and toxicity of intravenous (i.v.) methotrexate (MTX) and mercaptopurine (MP) as postremission intensification treatment for children with B-lineage acute lymphoblastic leukemia (ALL) at higher risk to relapse. PATIENTS AND METHODS: Eighty-three patients (age 1 to 20 years) with higher-risk B-lineage ALL were entered onto this protocol. Following standard four-drug remission induction, 80 patients received 12 intensive 2-week cycles of MTX/MP: MTX 200 mg/m2 i.v. push, then 800 mg/m2 i.v. 24-hour infusion on day 1; MP 200 mg/m2 i.v. in 20 minutes, then 800 mg/m2 i.v. 8-hour infusion day 2; MTX 20 mg/m2 intramuscularly day 8; and MP 50 mg/m2 by mouth days 8 to 14. Age-based triple intrathecal therapy (MTX, hydrocortisone, and cytarabine) was administered for CNS prophylaxis. Continuation therapy was weekly MTX/MP (as on days 8 to 14) for 2 years. RESULTS: Eighty-one patients (98%) entered remission. There were 28 relapses (marrow, n = 11; marrow and CNS, n = 2; isolated CNS, n = 9; testes, n = 5; ovaries, n = 1). No overt relapse occurred during the intensive phase of therapy. The event-free survival (EFS) rate at 4 years is 57.4% +/- 9.1% (SE). Hematologic, mucosal, and infectious toxicities were seen in 12%, 9%, and 5% of intensive MTX/MP courses, but were generally mild. CONCLUSION: Combined data from this and our previous trial suggest that intensive MTX/MP may produce long-term disease-free survival in 70 to 75% of children with B-lineage ALL. In comparison to other intensive regimens, intensive MTX/MP is easy to administer, effective, and relatively nontoxic. If patients at risk for failure of MTX/MP can be identified prospectively, more aggressive regimens could be restricted to this smaller (25% to 30%) cohort.

Adolescent↗
PubMed1992

Accumulation of high levels of methotrexate polyglutamates in lymphoblasts from children with hyperdiploid (greater than 50 chromosomes) B-lineage acute lymphoblastic leukemia: a Pediatric Oncology Group study.

Hyperdiploidy (greater than 50 chromosomes, or a DNA index greater than 1.16) confers a favorable prognosis in B-lineage acute lymphoblastic leukemia of childhood. Children with B-lineage acute lymphoblastic leukemia whose lymphoblasts at diagnosis accumulate high levels of methotrexate (MTX) and MTX polyglutamates (MTXPGs) in vitro experience a better event-free survival than those whose lymphoblasts do not (Blood 76:44, 1990). Lymphoblasts from 13 children with hyperdiploidy (greater than 50 chromosomes) accumulated high levels of MTX-PGs (1,095 and 571 to 2,346 pmol/10(9) cells [median and 25% to 75% intraquartile range]). These levels were higher than those in B-lineage lymphoblasts from 19 children with other aneuploidy (326 and 159 to 775 pmol/10(9) cells) and 15 children with diploidy (393 and 204 to 571 pmol/10(9) cells) (P = .0015). Chromosomal trisomies in hyperdiploid cases were highly nonrandom. Chromosome 9 was not one of the chromosomes involved in trisomies, even though this chromosome contains the gene for folate polyglutamate synthetase, which is the enzyme required for MTXPG synthesis. The correlation between MTXPG level and percentage of S-phase cells was weak, suggesting that increased levels of MTXPGs could not be attributed to elevated proportions of cells in active DNA synthesis. The ability of hyperdiploid lymphoblasts to accumulate high levels of MTXPGs may increase their sensitivity to MTX cytotoxicity, accounting in part for the improved outlook for hyperdiploid patients treated with regimens that emphasize MTX as a primary component of continuation therapy.

Child↗
PubMed1991

Recombinant interferon alfa given before and in combination with standard chemotherapy in children with acute lymphoblastic leukemia in first marrow relapse: a Pediatric Oncology Group pilot study.

Recombinant interferon alfa (rIFN-alpha) was given to 31 children with acute lymphoblastic leukemia (ALL) in first on-therapy marrow relapse as the sole treatment (30 megaunits/m2/d intravenously x 10 days) before standard four-drug reinduction and during multiagent continuation therapy (30 megaunits/m2 subcutaneously x 3 consecutive days every 3 weeks). After 10 days of rIFN-alpha, there were two partial remissions (PRs); seven additional patients had either greater than or equal to 25% reduction in the percentage of marrow blast cells or hypoplastic marrow. Two patients had progressive disease with an increase in leukocyte counts. All patients experienced influenza-like symptoms, and there were isolated instances of severe abdominal pain and personality change. Dose-limiting toxicity comprised grade III/IV transaminase elevation (two patients) and syncope with personality change (one patient). Twenty-three of 31 children (74%) subsequently achieved marrow remission using standard agents. One patient was taken off study during teniposide (VM-26) and cytarabine (ara-C) consolidation due to toxicity. Continuation therapy including rIFN-alpha pulse was well tolerated in the remaining children; only one patient required rIFN-alpha dosage reduction (for CNS toxicity). rIFN-alpha toxicity did not necessitate reductions in doses of standard chemotherapy agents or significant delays in therapy. Five patients remain in remission at 26+ to 36+ months; 13 patients relapsed in marrow, one in the meninges (7 months), and one in meninges, mediastinum, and lymph nodes (2 months). Two children were removed from study for marrow transplant. In summary, high-dose rIFN-alpha alone had a modest antileukemic effect. In contrast to the clinical experience with combined rIFN-alpha and chemotherapy in adults, rIFN-alpha given in a pulse-like manner throughout continuation therapy did not compromise the intensity of the standard chemotherapy regimen.

Adolescent↗
PubMed1990

Poor prognosis of children with pre-B acute lymphoblastic leukemia is associated with the t(1;19)(q23;p13): a Pediatric Oncology Group study.

The prognostic significance of chromosomal translocations, particularly t(1;19) (q23;p13), was evaluated in children with pre-B and early pre-B acute lymphoblastic leukemia (ALL). Patients were treated on a risk-based protocol of the Pediatric Oncology Group (POG) between February 1986 and May 1989. An abnormal clone was detected in 46% (130 of 285) of pre-B cases and 56% (380 of 679) of early pre-B cases. Translocation of any type was associated with a worse treatment outcome than other karyotypic abnormalities: 15 of 66 versus 3 of 64 failed therapy in the pre-B group (P = .001), and 37 of 141 versus 23 of 239 failed in the early pre-B group (P less than .001). The t(1;19) (q23;p13) occurred significantly more often in cases of pre-B ALL with a clonal abnormality than in early pre-B ALL cases (29 of 130 v 5 of 380, P less than .001). Among the 285 pre-B cases in which bone marrow was studied cytogenetically, those with t(1;19) had a significantly worse treatment outcome than all others (11 of 29 v 27 of 256 have failed therapy, P less than .001). This difference is significant (P less than .001) after adjustment for leukocyte count, age, and other relevant features. Cases with the t(1;19) also had a worse prognosis than pre-B patients with other translocations (4 of 37 have failed, P less than .01) or with any other karyotypic abnormality (7 of 101 have failed, P less than .001). We conclude that chromosomal translocations confer a worse prognosis for non-T, non-B-cell childhood ALL, and that the t(1;19) is largely responsible for the poor prognosis of the pre-B subgroup.

B-Lymphocytes↗
PubMed1989

Intermediate-dose intravenous methotrexate and mercaptopurine therapy for non-T, non-B acute lymphocytic leukemia of childhood: a Pediatric Oncology Group study.

Methotrexate (MTX) and mercaptopurine (MP) are the mainstays of continuation therapy for acute lymphocytic leukemia (ALL). These drugs are stored in tissues as active metabolites. Relapse in ALL might reflect failure to achieve adequate intracellular drug levels. Assured (parenteral) delivery of higher doses of MTX and MP should maximize tissue levels of these drugs by overcoming individual variations in absorption, metabolism, clearance, and compliance. Fifty-nine children with ALL at lower risk of relapse received 12 intensive MTX/MP courses immediately after 4 weeks of standard vincristine, prednisone, and asparaginase induction. Each 2-week intensive course included: MTX, 200 mg/m2 intravenous (IV) push then 800 mg/m2 IV over 24 hours on day 1; MP, 200 mg/m2 IV push then 800 mg/m2 IV over 8 hours on day 2; MTX, 20 mg/m2 intramuscularly on day 8; and MP, 50 mg/m2 orally daily on days 8 to 14. After the 6 months of intensive therapy, continuation therapy was weekly MTX/MP (as on days 8 to 14) for 1 or 2 years. Age-based MTX was given intrathecally (IT) for CNS prophylaxis. All patients entered remission. Three patients relapsed: bone marrow (at 24 and 37 months), and bone marrow and CNS (at 34 months). There were no isolated CNS relapses or deaths in remission. Event-free survival at 4 years is 94% (SE, 7%) by Kaplan-Meier analysis. Toxicities (infection, mucositis) occurred in less than 10% of intensive MTX/MP courses. However, a child with Down's syndrome withdrew after three courses because of recurrent severe mucositis. Further studies of this regimen are in progress.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

The big search: streamlining the textbook selection process.

Schools that serve hearing-impaired students must exercise special care in selecting textbooks to support classroom instruction. This article outlines the procedures developed and used at Kendall Demonstration Elementary School at Gallaudet University to evaluate and select a social studies textbook series. These procedures should apply to other subjects as well, and are offered as a resource model for other schools. Specific suggestions are made for every step in the process, including conducting a needs assessment, locating potential materials, defining roles of committee members, developing evaluation criteria and more. Emphasis is placed on conducting a comprehensive, manageable, and ultimately effective textbook search that supports the school's curriculum and satisfies the needs of students and teachers.

Book Selection↗
PubMed1989

Prognostic importance of the pre-B-cell immunophenotype and other presenting features in B-lineage childhood acute lymphoblastic leukemia: a Pediatric Oncology Group study.

We report the prognostic significance of the pre-B-cell immunophenotype and other presenting features, including blast cell karyotype, in a randomized clinical trial conducted from 1981 to 1986 for children with early pre-B (n = 685) or pre-B (n = 222) acute lymphoblastic leukemia (ALL). Patients greater than or equal to 1 year and less than or equal to 21 years of age who attained complete remission were stratified by conventional risk criteria and immunophenotype and then randomized to receive continuation therapy with either of two regimens of intensive chemotherapy, designated S (standard) and SAM (standard plus intermediate-dose methotrexate, 1 g/m2 every 8 weeks). The proportions of subjects achieving complete remission in the two phenotypically defined subgroups were identical, 96%. At a median follow-up time of 42 months, the overall probability of 4-year event-free survival (+/- SE) was 63% +/- 2% (pre-B = 51% +/- 5% and early pre-B = 66% +/- 3%). Children with pre-B ALL had significantly shorter durations of continuous complete remission (P = .0004); this association included both bone marrow and CNS remissions (P = .0004 and P = .02, respectively). In a univariate Cox regression analysis of potentially important prognostic factors, the pre-B immunophenotype was significantly related to a poorer outcome, as were other recognized biologic and clinical features (eg, pseudodiploidy, older age, male sex, black race, and a higher WBC). It retained its prognostic strength in a multivariate model based on age, WBC, ploidy, and sex. The risk of failure at any point in the clinical course of a child with the pre-B immunophenotype was 1.8 times as great as that in a patient lacking this feature but otherwise having an equivalent risk status. It should be stressed that the predictive value of any of the significant characteristics identified in this study could diminish in the context of another, more effective treatment program. Nevertheless, our major conclusion, that children with pre-B ALL fare worse than those with early pre-B disease in a contemporary clinical trial has implications for stratified randomization of patients and the design of risk-specific treatment protocols.

Analysis of Variance↗
PubMed1988

Single- vs double-lumen central venous catheters in pediatric oncology patients.

Double-lumen central venous catheters (CVCs) have been introduced recently for use in pediatric patients. The objective of our study was to determine if double-lumen CVC usage increased the possibility of infectious and mechanical complications compared with that of traditional single-lumen CVCs in a population at high risk for infection (oncology patients). Thirty pediatric patients (2.5 +/- 3.0 years old; mean +/- SD) who received single-lumen CVCs were compared with 31 patients (5.9 +/- 4.7 years old) who received double-lumen CVCs. The incidence of infectious complications was compared while controlling for potential confounding variables. Fifty-seven percent (17/30) of patients in the single-lumen group experienced bacteremia or cellulitis that required removal of six catheters compared with a rate of 52% (16/31) and nine catheter removals in the double-lumen group. Fewer manipulations occurred in the single-lumen group compared with the double-lumen group, but the incidence of mechanical complications tended to be greater. When managed carefully, double-lumen CVCs were not associated with a greater risk of infection than single-lumen CVCs.

Bacterial Infections↗
PubMed1988

Clinical trial of etoposide (VP-16) in children with recurrent malignant solid tumors. A phase II study from the Pediatric Oncology Group.

Etoposide (VP-16), 150 mg/M2, given intravenously daily for 3 days every 3 weeks resulted in 3 complete responses and 6 partial responses in 154 patients with a spectrum of recurrent malignant solid tumors. There was evidence of disease control in an additional 37 patients (27 mixed responses and 10 stable disease). These responses occurred primarily in patients with Ewing's sarcoma, Hodgkin's disease, neuroblastoma and rhabdomyosarcoma. Most of the patients had every extensive prior therapy; however prior therapy with teniposide (VM-26), the congener of VP-16, did not seem to preclude responses to the latter drug. Myelosuppression was the principal form of toxicity. Neutropenia characterized by absolute neutrophil counts of 0.5 to 0.9 x 10(9)/L occurred in one-half of the patients, and thrombopenia with platelet counts of less than 25 to 49 x 10(9)/L in one-fourth. These results demonstrate a favorable therapeutic index for VP-16 in several recurrent childhood solid tumors, supporting its use as a component of primary therapy for these diseases.

Adolescent↗
PubMed1988

Intravenous immunoglobulin may lessen all forms of infection in patients receiving allogeneic bone marrow transplantation for acute lymphoblastic leukemia: a pediatric oncology group study.

Fifty patients with refractory acute lymphoblastic leukemia underwent allogeneic bone marrow transplantation after conditioning with high-dose cytosine arabinoside and fractionated total body irradiation. Twenty-nine received intravenous immunoglobulin (i.v.Ig) infusion, primarily to prevent cytomegalovirus infection, and 21 did not. The two groups were biologically comparable. Seven (24.5%) of the i.v.Ig-treated and 14 (66.7%) of the non-i.v.Ig-treated patients developed systemic viral, fungal or bacterial infections and/or interstitial pneumonitis (p less than 0.005), which were fatal in three and 12 cases respectively (p less than 0.001). Currently, 23 (79.3%) of the 29 i.v.Ig-treated and eight (38.1%) of the 21 non-i.v.Ig-treated patients are alive and well (p less than 0.01). We conclude that prophylactic i.v.Ig infusions may reduce the frequency of all forms of serious infection in patients with acute lymphoblastic leukemia undergoing allogeneic marrow transplantation, and thereby improve their survival expectation.

Bone Marrow Transplantation↗
PubMed1987

Functional domains of SIR4, a gene required for position effect regulation in Saccharomyces cerevisiae.

The product of the Saccharomyces cerevisiae SIR4 gene, in conjunction with at least three other gene products, prevents expression of mating-type genes resident at loci at either end of chromosome III, but not of the same genes resident at the MAT locus in the middle of the chromosome. To address the mechanism of this novel position effect regulation, we have conducted a structural and genetic analysis of the SIR4 gene. We have determined the nucleotide sequence of the gene and found that it encodes a lysine-rich, serine-rich protein of 152 kilodaltons. Expression of the carboxy half of the protein complements a chromosomal nonsense mutation of sir4 but not a complete deletion of the gene. These results suggest that SIR4 protein activity resides in two portions of the molecule, but that these domains need not be covalently linked to execute their biological function. We also found that high-level expression of the carboxy domain of the protein yields dominant derepression of the silent loci. This anti-Sir activity can be reversed by increased expression of the SIR3 gene, whose product is normally also required for maintaining repression of the silent loci. These results are consistent with the hypothesis that SIR3 and SIR4 proteins physically associate to form a multicomponent complex required for repression of the silent mating-type loci.

Amino Acid Sequence↗
PubMed1987

A totally implanted venous access system used in pediatric patients with cancer.

A safe and effective method of venous access is important in the care and treatment of patients with malignancies. A recently available totally implantable venous access system offers advantages over traditional central vein catheters (Broviac and Hickman, Houston). We report our experience with the implanted venous access system used in 31 pediatric patients with malignancies. The mean age of the patients was 7 years (range, 6 months to 17 years), and the mean indwelling time of the catheters was 232 days (range, 14 to 607 days; total patient days, 7,198). The catheters were used to administer chemotherapy, drugs, blood products, and parenteral nutrition, as well as to draw blood. Clotting occurred in the catheters on four occasions, requiring removal of two catheters. Fever occurred in eight patients; one developed a local infection at the site of implantation and four developed bacteremia. Our use of the implanted venous access system in children resulted in a lower rate of infection compared with that when the traditional Broviac and Hickman catheters were used, and simplified patient management.

Adolescent↗
PubMed1987

Analysis of surface antigen profile, TdT expression, and T cell receptor gene rearrangement for maturational staging of leukemic T cells: a pediatric oncology group study.

By using monoclonal antibodies specific for T lineage surface antigens, neoplastic T cells from 53 children with T cell acute lymphoblastic leukemia and T cell non-Hodgkin's lymphoma were analyzed and assigned to phenotypically defined stages of T cell maturation. Cells were also analyzed for T cell antigen receptor beta-chain gene and immunoglobulin heavy and light chain gene rearrangements. Clonal rearrangements of T cell antigen receptor beta-chain gene and a germ-line configuration of the immunoglobulin genes were found in cells from all cases. The expression of the terminal deoxynucleotidyl transferase (TdT) in leukemic T cells was studied by both qualitative immunofluorescence and quantitative enzyme immunoassay, and the level of TdT expression was correlated with maturational stages. Lymphoblasts classified as prethymic (3 patients) did not express detectable TdT. In contrast, cells from approximately 60% of the patients with early (15 patients) or intermediate (19 patients) thymocytic phenotypes and approximately 40% of the patients with mature thymocytic phenotype (16 patients) were positive for TdT. Thus, in these leukemic clones TdT was randomly expressed and showed no correlation with maturational stage.

Antibodies, Monoclonal↗
PubMed1983

Influence of dietary polyunsaturated fatty acids on renal & aortic prostaglandin synthesis in 1 kidney 1 clip Goldblatt hypertensive rats.

To study the influence of dietary modification on prostaglandin synthesis and on blood pressure regulation, the effects of dietary enrichment with linolenic or linoleic acid was compared with standard rat chow in 3 groups of 13 rats before and after renal artery constriction and contralateral nephrectomy. Before renal artery constriction 4 weeks supplementation with 40 en% linseed oil (53% linolenic acid) increased renal linolenic acid, decreased arachidonic acid, and suppressed synthesis of 6-keto-PGF1 alpha and PGE2 by renal homogenates (33% and 38% respectively, p less than 0.01) compared with standard diet. Rats fed on 40 en % sunflower seed oil (63% linoleic acid) increased renal prostaglandin synthesis (p less than 0.05) compared with linseed oil, but not compared with standard diet. Seven weeks after renal artery constriction renal and aortic 6-keto-PGF1 alpha and PGE2 were suppressed 30% to 50% (p less than 0.05) by linseed oil supplements compared with sunflower seed oil and standard diets. In the sunflower seed oil group aortic 6-keto-PGF1 alpha correlated (r = 0.75, p less than 0.02) with final systolic blood pressure. Final systolic blood pressures were similar in linseed oil (152.9 mm Hg +/- se 3.3, sunflower oil (155.1 +/- se 6.6) and standard diet group (159.0 +/- se 4.2). Thus dietary linseed oil suppressed renal and aortic prostaglandin synthesis but did not accentuate renal hypertension, and linoleic acid supplementation did not protect against 1 kidney 1 clip renal hypertension.

Animals↗