Biomedical subjects

A H Ragab

Publications and source records attributed to A H Ragab.

At least 37 records · Page 2Linked to original sources

PubMed1991

In vitro enhancement of natural killer cell activity against herpesvirus-infected targets in patients with acute lymphocytic leukemia.

The present study was carried out to determine whether natural killer (NK) activity against virus-infected target cells could be enhanced in peripheral blood lymphocytes (PBL) taken from patients with acute lymphocytic leukemia. Nonspecific cell-mediated killing of heterologous herpesvirus-infected B lymphoblastoid targets could be enhanced by pretreating PBL with interferons-alpha or -gamma, or with interleukin-2. NK activity was substantially enhanced over that of untreated cells, and virtually all cytolytic activity was attributable to CD16+ NK cells. Pretreatment of PBL with a combination of cytokines resulted in additive, but never synergistic enhancement of NK activity. The results suggest that cytokine therapy may provide a useful means for treating severe varicella zoster infections in immunocompromised children.

Cell Line, Transformed↗

PubMed1991

Ovarian tumors in relapsing acute lymphoblastic leukemia: a review of 23 cases.

Five cases of relapsing acute lymphocytic leukemia (ALL) presenting as an ovarian tumor have been treated at this institution, representing the largest reported series. In a review of the literature we identified 18 additional cases of ovarian leukemic relapse. Together, these 23 patients form the basis for this report. Abdominal pain is the most common presenting symptom of ovarian leukemia. An abdominal mass is usually palpable, and at least four patients had hydronephrosis. Nine patients had documented bilateral ovarian involvement; however, bilateral disease was not a poor prognostic sign. Most ovarian relapses occurred more than 36 months after the original diagnosis of ALL, with these "late'h relapsers responding more favorably to treatment than "early" relapsers. Definitive statements can not be made from a retrospective review of 23 case reports; however, salpingooophorectomy had no obvious advantage over simple biopsy, and there was no obvious advantage to the routine use of radiation therapy. Most failures in treating ovarian leukemia occurred within 2 years. Most failures were systemic rather than local, illustrating the need for aggressive multiagent systemic chemotherapy. Survival after ovarian leukemic relapse is possible, with eight of the 23 patients alive and in complete continuous remission following the ovarian relapse (median follow-up since relapse, 42 months; range, 2 to 135+ months). With the use of more intensive chemotherapy in recent protocols, the frequency of ovarian leukemic relapses appears to be decreasing. At this institution, no child with ALL diagnosed in the 1980s has subsequently developed an ovarian relapse.

Adolescent↗

PubMed1991

Phase II study of 13-cis-retinoic acid in pediatric patients with acute nonlymphocytic leukemia--a Pediatric Oncology Group study.

Forty-one patients with refractory acute non-lymphocytic leukemia (ANLL) in relapse were treated with 13-cis-retinoic acid (cRA) as salvage therapy. The cRA was given as a single oral dose of 100 mg/m2/day for 4 weeks. One patient achieved a complete remission and two patients achieved a partial remission with reduction of the bone marrow blast count from 40 to 20% after the first course. We recommend further study of cRA in combination with other agents in the treatment of ANLL in children.

Adolescent↗

PubMed1991

Clinical features and results of therapy for children with paraspinal soft tissue sarcoma: a report of the Intergroup Rhabdomyosarcoma Study.

Soft tissue sarcomas of the paraspinal region comprised 3.3% (56 of 1,688) of the patients entered and eligible on Intergroup Rhabdomyosarcoma Studies I (IRS-I) and II (IRS-II) (1972 to 1984). These lesions tended to be greater than 5 cm in diameter at diagnosis, invaded the spinal extradural space, and were of the extraosseous Ewing's sarcoma or undifferentiated sarcoma subtype in 55% (30 of 56) of the cases. Patients with tumors in clinical groups II, III, and IV were treated with radiotherapy (XRT) and vincristine-dactinomycin (VA) or VA plus cyclophosphamide (VAC) +/- doxorubicin. Clinical group I patients treated on IRS-II did not receive XRT, while those on IRS-I were randomized to receive VAC +/- XRT. Forty-four of the paraspinal patients (79%) achieved a complete response (CR) compared with 77% (1,260 of 1,632) for patients with disease in other sites. Twenty-seven patients (55%) subsequently relapsed (five local, three regional, four local and distant, and 14 distant). The proportion of patients surviving 5 years by clinical group (stage) from I to IV were 50%, 50%, 62%, and 27%, respectively. Paraspinal patients had somewhat poorer survival than patients with disease in other sites, both in IRS-I and IRS-II; the percentage of paraspinal patients surviving 5 years was 50% and 52% for IRS-I and IRS-II, respectively, whereas these percentages were 55% and 63% for patients with disease in other sites. Histology did not influence the CR rate, but unexpectedly, patients who had embryonal rhabdomyosarcoma (RMS) had the poorest overall survival rate. We concluded that patients with paraspinal lesions may require extended-field radiation therapy to reduce the high local failure rate and more intensive chemotherapy to achieve better local and systemic tumor control.

Child↗

PubMed1991

Nitrogen mustard, vincristine, procarbazine, and prednisone as adjuvant chemotherapy in the treatment of medulloblastoma. A Pediatric Oncology Group study.

In a randomized postoperative trial, adjuvant post-irradiation chemotherapy, consisting of nitrogen mustard, vincristine, procarbazine, and prednisone (MOPP), was tested versus radiation therapy alone for newly diagnosed medulloblastoma in patients between 1 and 21 years of age. Patients treated with irradiation plus MOPP had a statistically significant increase in overall survival rate at 5 years posttreatment compared to patients treated with radiation therapy alone (74% vs. 56%; p = 0.06, adjusted for race and gender). Although the overall study failed to show a statistically significant advantage for irradiation plus MOPP in event-free survival (p = 0.18), statistical significance was attained in children 5 years of age or older (p = 0.05). More severe hematological toxicities occurred in the group with irradiation plus MOPP; however, this hematotoxicity appeared to be tolerable and acceptable. These results suggest that patients may benefit from combined irradiation and chemotherapy following surgery for medulloblastoma.

Adolescent↗

PubMed1990

Abnormal vitamin B6 status in childhood leukemia.

Vitamin B6 is involved in many biological processes of potential relevance to carcinogenesis and tumor growth, including DNA synthesis and maintenance of immunocompetence, yet very little information exists on B6 nutritional status in childhood leukemia. Using a radioenzymatic assay, the authors measured plasma pyridoxal 5'-phosphate (PLP), the biologically active form of B6, in 11 newly diagnosed untreated children with leukemia and 11 age-matched controls. The children with leukemia had significantly lower PLP levels than the controls. In 26 additional leukemia patients and 26 additional controls, a high-performance liquid chromatography assay also demonstrated lower plasma PLP levels in childhood leukemia compared with controls. These differences were significant for both acute lymphoblastic leukemia (ALL) and for acute nonlymphoblastic leukemia (ANLL). The PLP values did not correlate with indices of leukemia cell burden, but did correlate with reported B6 intake, suggesting that illness-related diet changes are at least partially responsible for the low PLP levels. Before any chemotherapy, overall nutritional status was suboptimal in 53% of ALL cases and 57% of ANLL cases. Newly diagnosed children with leukemia have suboptimal overall nutrition as well as suboptimal vitamin B6 status.

Adolescent↗

PubMed1990

Coding sequences of the tal-1 gene are disrupted by chromosome translocation in human T cell leukemia.

The tal-1 proto-oncogene encodes a helix-loop-helix DNA-binding protein that has been implicated in the formation of T cell acute lymphoblastic leukemia (T-ALL). Patients with T-ALL harbor structural rearrangements of tal-1 that result from either local DNA deletion or t(1;14)(p34;q11) chromosome translocation. By analyzing t(1;14)(p34;q11) chromosomes from a series of patients, we have now identified a discrete region of tal-1 wherein most of the translocation breakpoints occur. Moreover, mapping of tal-1 genomic DNA revealed that coding exons are situated on both sides of the t(1;14)(p34;q11) major breakpoint region. Hence, the translocated allele of tal-1 is truncated in a manner that reduces its amino acid coding potential.

Adult↗

PubMed1990

The t(1;14)(p34;q11) is nonrandom and restricted to T-cell acute lymphoblastic leukemia: a Pediatric Oncology Group study.

We report the nonrandom occurrence, frequency, and degree of immunophenotype association of the t(1;14)(p34;q11) in children with acute lymphoblastic leukemia (ALL). This chromosomal abnormality occurred in leukemia cells from 5 of 1,630 (0.3%) consecutive children with newly diagnosed ALL who were entered on a single Pediatric Oncology Group classification study (POG 8600) between January 1986 and February 1989. The frequency of the t(1;14) was 3% (5 of 168 cases) in children with T-cell ALL. All five cases had pseudodiploid karyotypes, and in 3 cases the t(1;14) was accompanied by a deletion of the long arm of chromosome 6. This translocation is of special interest because the breakpoint on chromosome 14 in band q11 corresponds to the assigned locus of the T-cell receptor alpha/delta chain gene. All five of our patients and three cases reported previously have had T-cell ALL. These findings, considered together, suggest that this translocation is specific for T-cell ALL and that a gene in the 1p34 region may play an important role in malignant transformation of thymocytes.

Adolescent↗

PubMed1990

Cytotoxicity of purified Leu 19+ cells from the peripheral blood of children with acute lymphocytic leukemia.

Several investigators have reported decreased natural killer cell activity of the peripheral blood from children with acute leukemia both at diagnosis and in relapse. This study was to determine whether this decreased natural killer activity is the result of a diminished number or defective function of natural killer cells or both. The percentage of Leu 19+ (NKH-1, CD56) and the lytic activity of a purified Leu 19+ population from the peripheral blood of children with acute lymphocytic leukemia as well as from healthy children were determined. This cell population mediates most natural killer and natural killer-like activity in the peripheral blood. Twenty-three children with acute lymphocytic leukemia (16 at diagnosis, seven in relapse) as well as six control children were studied. The percentage of Leu 19+ cells was significantly lower in the blood of children either at initial diagnosis (median, 3%; P less than 0.005) or in relapse (median, 1%; P less than 0.01) than that for the control children (median, 12.5%). The cytotoxicity of peripheral blood mononuclear cells (PBMC) against K562 in 3-hour 51Cr release assay was significantly lower for patients either at diagnosis (median, 8.5 lytic units[LU]/10(7) cells; P less than 0.005) or in relapse (median, 3 LU/10(7) cells; P less than 0.005) than that for normal controls (median, 97 LU/10(7) cells). The lytic activity of a fluorescent activated cell sorter (FACS) purified Leu 19+ population was evaluated. The Leu 19+ cells were sorted from PBMC of 11 children with acute lymphocytic leukemia who had more than 2% Leu 19+ cells in their PBMC (nine at diagnosis and two in relapse). The lytic activity of sorted Leu 19+ cells was significantly (P less than 0.04) lower for patients at initial diagnosis (median, 45 LU/10(7) cells) than that for normal control children (median, 317 LU/10(7) cells). One of the two children studied at relapse had low Leu 19+ lytic activity. The authors concluded that (1) The percentage of Leu 19+ cells in the peripheral blood of the majority of children with acute lymphocytic leukemia either at diagnosis or in relapse is below normal; (2) The lytic activity of PBMC from the majority of children with acute lymphocytic leukemia is reduced both at diagnosis and in relapse; and (3) The lytic activity of Leu 19+ purified PBMC is reduced in the majority of children with acute lymphocytic leukemia. These findings confirm the defective natural killer cell profile in children with acute lymphocytic leukemia both at the time of diagnosis and in relapse.

Adolescent↗

PubMed1990

Effects of low molecular weight B-cell growth factor on proliferation of leukemic cells from children with B-cell precursor-acute lymphoblastic leukemia.

Recently, low-molecular-weight B-cell growth factor (LMW-BCGF) has been reported to stimulate growth of leukemic cells from B-cell precursor-acute lymphoblastic leukemia (BCP-ALL). We further investigated the effects of LMW-BCGF on proliferation of leukemic clonogenic (progenitor) and nonclonogenic (progeny) cells from children with BCP-ALL (28 patients) and B-cell ALL (two patients). Patients were either at diagnosis (n = 18) or in relapse (n = 12). Response of leukemic progenitor cells was determined by culturing cells (10(5) cells/mL) in methylcellulose with 0.1 U/mL LMW-BCGF. Colonies (greater than 20 cells) were counted at day 7. The response of the leukemic progeny population was determined by DNA synthesis studies using tritiated-thymidine and by DNA quantitation with propidiumiodide for determination of cell-cycle status. LMW-BCGF supported growth of leukemic progenitor cells from 20 of 28 (71%) BCP-ALL and two of two B-cell ALL patients. Colony numbers ranged from 7 to 2,400 (mean 145, median 45). A dose-response effect in colony growth was noted, with an apparent plateau at approximately 2.0 U/mL LMW-BCGF. Colony cells were primarily of leukemic phenotype (CD19+/CD10+/-). LMW-BCGF also induced significant increases in leukemic progeny cell proliferation as measured by both thymidine incorporation (stimulation indexes of 1.6 to 34) and by cell-cycle assay (percentage S+ G2/M stimulation indexes of 1.6 to 6). LMW-BCGF was more effective in stimulating leukemic proliferation than three recombinant interleukins (rIL-2, rIL-3, rIL-4), although rIL-3 was able to support colony growth in 4 of 11 patients. These results indicate that LMW-BCGF and, to a lesser degree rIL-3, are able to stimulate proliferation of BCP-ALL progenitor and progeny cells, whereas rIL-2 and rIL-4 do not support progenitor cell proliferation and have only marginal effects on leukemic progeny cell proliferation.

Bone Marrow↗

PubMed1990

Assay of lymphokine-activated killer activity generated from bone marrow cells of children with acute lymphoblastic leukemia.

We recently reported that low molecular weight B-cell growth factor (LMW-BCGF) plus recombinant interleukin-2 (rIL-2) synergistically induced lymphokine-activated killer (LAK) activity from the bone marrow (BM) cells of children with acute lymphoblastic leukemia (ALL). The kinetics of cell growth, antigenic phenotype, and lytic activity of the generated effector cells were further analyzed in this study. BM cells from ALL patients with active disease and in complete remission (CR) were cultured with a combination of LMW-BCGF and rIL-2. Monoclonal antibodies (anti-CD3 and anti-Leu 19) and immunomagnetic beads were used to separate LAK cells into three subsets: CD3+/Leu 19-, CD3+/Leu 19+, and CD3-/Leu 19+. Cytotoxicity assays with different subsets were performed versus K562, Raji, and autologous leukemic cells, using a 3-hour 51Cr release test. There was a significant cell expansion of 54-fold (mean value) for CD3+ cells and 15-fold for Leu 19+ cells in culture with LMW-BCGF plus rIL-2 for 7 to 14 days, whereas no cell expansion was observed in culture with rIL-2 alone. Although NK activity (K562) was generated from leukemic BM cells in culture with rIL-2 alone, it is only about one third of that generated in culture with rIL-2 plus LMW-BCGF. Analysis of lytic activity of cells generated in the latter cultures demonstrated that CD3-/Leu 19+ cells expressed highest lytic activity against NK-sensitive K562 cells as well as against NK-resistant Raji cells. CD3+/Leu 19+ cells showed median cytotoxicity, and CD3+Leu 19- cells mediated only minimal cytotoxic activity. Also, lytic activity of CD3-/Leu 19+ cells against autologous leukemic blasts was noted in patients with active disease. Our results demonstrate that LAK activity generated from BM cells by LMW-BCGF and r-IL2 is mediated mainly by two types of Leu 19+ cells: CD3-/Leu 19+ NK cells and CD3-/Leu 19+ T cells. Although CD3+ T cells (both Leu 19+ and Leu 19-) mediated less antitumor cytotoxicity than CD3-/Leu 19+ cells, the former cells were the major expanding cell population in culture with LMW-BCGF and rIL-2. The new culture system may be effective in generation of cells with LAK activity for therapeutic use.

Adolescent↗

PubMed1990

Aziridinylbenzoquinone (AZQ) in the treatment of recurrent pediatric brain and other malignant solid tumors. A Pediatric Oncology Group phase II study.

To assess the response rates and toxicity of AZQ in children with recurrent brain and other malignant solid tumors, a phase II study was implemented by the Pediatric Oncology Group. Eligible patients received AZQ 18 mg/M2/week i.v. for 4 doses followed by a 2 week rest period. Each dose was given over four hours (1/3 over the initial 20 minutes). After the first year, the dosage was reduced to 13 mg/M2 due to myelotoxicity resulting in treatment delays. No objective responses were observed in 73 evaluable children with various non-central nervous system tumors. Of the 91 patients with brain tumors, there were 4 CR's and 2 PR's in patients with astrocytoma, ependymoma, glioblastoma multiforme, oligodendroglioma, brain stem glioma and intracranial yolk sac tumor (median duration, 10 months; range, 2-20+ months). Three of 4 CR's were achieved with a dosage of 18 mg/M2/week. An additional 13 children with brain tumors experienced stable or improved disease (duration, 2-36 + months; median 7.5 months). The principal toxicity was myelosuppression which was cumulative but there were also 3 allergic reactions to AZQ. We conclude that for selected brain tumors, the rates of objective response and stable disease plus the duration of responses support further assessment of AZQ in combination with other agents. Furthermore, the 18 mg/M2 dosage may provide better responses.

Adolescent↗

PubMed1990

A phase II trial of continuous-infusion 6-mercaptopurine for childhood solid tumors.

A phase II pediatric trial of a continuous intravenous infusion of 6-mercaptopurine (6-MP) in patients with refractory solid tumors or lymphoma was performed. The dosing schedule of 50 mg/m2 per hour for 48 h was chosen to produce optimal cytotoxic concentrations of 6-MP. There were no complete or partial responses in the 40 patients entered in the trial. Accrual was sufficient for the conclusion to be drawn that there was greater than 95% probability that the true response rate was no greater than 22% and 26% in osteosarcoma and Ewing's sarcoma, respectively. Dose-limiting toxicity was observed in one-third of the patients and included reversible hepatotoxicity, myelosuppression, and mucositis. The excellent penetration of drug into the cerebrospinal fluid (CSF) suggests that future trials of this intravenous dosing schedule should be conducted on tumors of the CNS.

Adolescent↗

PubMed1990

Non-Hodgkin's lymphoma presenting as a rectal polyp in a child.

Primary lymphoma of the rectum is extremely rare in children. We report here a 10-year-old boy with localized non-Hodgkin's lymphoma, discovered within a rectal polyp. The literature on childhood rectal lymphomas is reviewed. This case illustrates the importance of considering the possibility of malignancy with rectal polyps, even in children.

Child↗

PubMed1990

Effects of recombinant interferon-gamma and interleukin-2 on the generation of lymphokine-activated killer cells in vitro.

In order to determine if recombinant interferon-gamma (rIFN-gamma) can augment the effect of recombinant interleukin-2 (rIL-2) in generating lymphokine-activated killer (LAK) cells, we have incubated normal peripheral blood mononuclear cells (PBMC) with these lymphokines for 3 days and then tested their LAK and natural killer (NK) cell activity. We have found that LAK activity in PBMC from 13 out of 13 normal donors was increased by the combined lymphokines above that due to either lymphokine alone, provided that rIL-2 was present at suboptimal concentration: Optimal levels of rIFN-gamma (100 U/ml) were able to enhance the LAK-inducing activity of suboptimal levels (5 U/ml) but not optimal levels (100 U/ml) of rIL-2. NK activity showed a similar response to these concentrations of lymphokines. Activation of LAK/NK cells was accompanied by increases in the percentages of Leu 19+ (CD56) cells and TAC+ (IL-2-receptor) cells, and in the intensity of TAC antigen expression. These results indicate that combination rIFN-gamma and rIL-2 may be more effective in generating LAK/NK cells than rIL-2 alone, particularly with suboptimal concentrations of rIL-2 such as occur during continuous infusion therapy with this agent.

Dose-Response Relationship, Drug↗

PubMed1990

Pharmacokinetics of recombinant interleukin-2 in children with malignancies: a Pediatric Oncology Group study.

To develop effective interleukin-2 (IL-2) protocols for pediatric malignancies, it is important to define IL-2 pharmacokinetics in children. In a phase I trial, we studied IL-2 pharmacokinetics in seven children, aged 6-18, five with leukemia, one with neuroblastoma, and one with rhabdomyosarcoma. IL-2 was administered as a 15-min i.v. infusion of either 1 X 10(6) CU/m2/dose or 3 X 10(6) CU/m2/dose (every Monday, Wednesday, and Friday for 3 weeks). IL-2 levels were determined using an IL-2-dependent murine T lymphocyte cell line bioassay. Peak IL-2 levels of 120-426 and 330-740 CU/ml were achieved after the lower and higher doses, respectively. Pediatric IL-2 kinetics resembled data reported for adults, fitting a two-compartment model (least-squares-regression technique), with an alpha half-life of 14.0 +/- 5.6 min (range, 6.3-23.1) and a beta half-life of 51.4 +/- 10.7 min (range, 33.0-66.0). The volume of distribution approximated total extracellular fluid (mean, 0.18 L/kg). Further clinical trials are needed to identify which pediatric malignancies are sensitive to immunotherapy and to establish the optimal treatment regimens.

Adolescent↗

PubMed1989

Human myeloperoxidase gene expression in acute leukemia.

To evaluate the relationship between myeloperoxidase (MPO) gene expression and specific lineages of hematopoietic differentiation, we analyzed expression of the MPO gene in a variety of normal and leukemic human cells. As a first step, we synthesized several oligonucleotide probes and isolated cDNA clones for the MPO gene. MPO expression was detected in most acute myeloid leukemias, and the level of expression correlated well with cytochemical enzymatic activity. No MPO message was detected in pure lymphoid leukemias, whereas very low basal levels of MPO transcripts were found in normal bone marrows. In four cases of acute undifferentiated leukemias cytochemically negative for MPO, significant levels of MPO transcripts were detected, suggesting a myeloid origin for these cases. These results indicate that MPO gene expression may serve as an additional marker for subclassification of acute leukemias and may be used to identify leukemic cells arrested at an early stage of the myeloid differentiation pathway.

Blotting, Northern↗

PubMed1989

A phase I study of interleukin-2 in children with cancer and evaluation of clinical and immunologic status during therapy. A Pediatric Oncology Group Study.

The authors performed a Phase I study to assess the toxicity and hematologic effect of recombinant human interleukin-2 (rIL-2) in seven children with advanced malignancies. The rIL-2 was given as a bolus injection of 1 or 3 X 10(6) U/m2/dose three times a week (Monday, Wednesday, and Friday) for 3 weeks. No life-threatening toxicity occurred with the dose of 1 X 10(6) U/m2 of rIL-2. At a dose of 3 X 10(6) U/m2, therapy had to be terminated due to cardiovascular toxicity in two patients. Toxic effects at low-dose rIL-2 included fever, nausea, vomiting, and mild hypotension. High-dose rIL-2 toxicity included fluid retention, increased creatinine, oliguria, elevated liver enzymes, and significant hypotension. Immunologic studies showed that rIL-2 caused a drop in the number of circulating peripheral blood mononuclear cells, T-cells, and natural killer cells which returned to pretherapy levels or above by 24 to 48 hours. The rIL-2 exerted no growth or stimulatory activity on the leukemic cell population. To the authors' knowledge, this is the first report of a Phase I study of IL-2 therapy in children.

Adolescent↗