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K Bradstock

Publications and source records attributed to K Bradstock.

At least 19 recordsLinked to original sources

Effect of the Philadelphia chromosome on minimal residual disease in acute lymphoblastic leukemia.

The Philadelphia translocation is associated with a poor prognosis in adults and children with acute lymphoblastic leukemia, even though the majority of patients achieve remission. To test the hypothesis that the translocation leads to drug resistance in vivo, we studied 61 children and 20 adults with acute lymphoblastic leukemia and used the level of minimal residual disease at the end of induction as the measure of drug resistance in vivo. In children the presence of the translocation was associated with a significant increase in residual disease, indicating higher drug resistance in vivo; five of seven Philadelphia-positive children but only five of 54 Philadelphia-negative children had a minimal residual disease level >10(-3), a level which is associated with a high risk of relapse in childhood acute lymphoblastic leukemia of standard risk. By contrast, in adults, residual disease and hence drug resistance was already higher than in children, and the presence of the Philadelphia translocation in seven patients had no obvious additional effect. We conclude that the Philadelphia chromosome may increase resistance to drugs in vivo in children, but not detectably in adults.

Adolescent

Australian Leukaemia Study Group myeloma II: a randomized trial of intensive combination chemotherapy with or without interferon in patients with myeloma.

The Australian Leukaemia Study Group has performed a randomized trial of interferon alpha-2A (Roferon-A) as a co-induction agent together with intensive combination chemotherapy and as maintenance following completion of 12 cycles of induction treatment. When used as a co-induction agent, interferon-alpha did not improve response rates, time-to-treatment failure, or overall survival. Patients who had interferon together with intensive combination therapy (PCAB: prednisone 60 mg/m2 days 1-5, cyclophosphamide 600 mg/m2 day 1, BCNU 30 mg/m2 day 1, doxorubicin 30 mg/m2 day 1, repeated every 28 d for a total of 12 cycles) had more leucocyte and granulocyte toxicity and received a lower dose intensive of cytotoxic drugs than those patients who received PCAB without interferon. There was a trend towards prolongation of plateau phase which did not reach significance. Interferon, however, did improve the survival of patients who achieved plateau; for those patients interferon was associated with a 33% decrease in the rate of death after adjusting for initial beta-2 microglobulin level.

Activities of Daily Living

Relationship between minimal residual disease and outcome in adult acute lymphoblastic leukemia.

In children with acute lymphoblastic leukemia (ALL), the level of minimal residual disease (MRD) at the end of induction strongly predicts outcome, presumably because it measures both drug sensitivity and the number of leukemic cells requiring elimination. Children with high levels (> 10(-3) leukemic cells per marrow cell) nearly always relapse, whereas those with low levels (<2 x 10(-5)) seldom do. However, the importance of MRD in adult ALL is unclear. We studied 27 patients aged 14 to 74 who were treated with a standard protocol and who attained morphological remission. MRD in the marrow at first remission was quantified by using the polymerase chain reaction (PCR), with the rearranged immunoglobulin heavy chain gene as a molecular marker. Levels of MRD varied from 3 x 10(-1) to <7 x 10(-7). The probability of long-term relapse-free survival was significantly related to the level of MRD and only one of nine patients with MRD >10(-3) did not relapse. For patients who did relapse, there was an inverse relationship between MRD level and the length of remission. Overall, MRD in adults in whom a translocation had not been identified was significantly higher than in comparably-treated children, suggesting that ALL in adults is more drug-resistant than in children.

Adolescent

A randomized study of high-dose cytarabine in induction in acute myeloid leukemia.

High-dose cytarabine (ara-c) may overcome cytarabine resistance in leukemic blasts. It has been used as a successful salvage and in postremission therapy but not as initial induction treatment. Patients aged 15 to 60 years, presenting with newly diagnosed acute myeloid leukemia (AML) were randomized to receive either high-dose cytarabine, 3 g/m2 12 hourly on days 1, 3, 5, and 7 for 8 doses, daunorubicin 50 mg/m2 days 1 to 3, etoposide 75 mg/m2 days 1 to 7, (HIDAC-3-7) or standard dose cytarabine 100 mg/m2 continuous intravenous infusion for 7 days with daunorubicin and etoposide at the same dose and schedule as above (7-3-7). Patients could receive a second or third induction course if complete remission (CR) was not achieved. All patients received the same postinduction consolidation therapy (5-2-5) for 2 courses. Eligible patients had no prior chemotherapy or myelodysplastic disease. Patients have been followed for a median of 4.5 years. Of 301 patients treated, complete response (CR) was achieved in 71% with HIDAC-3-7 and 74% with 7-3-7. For patients in CR, the estimated median remission duration was 45 months with HIDAC-3-7 and 12 months with 7-3-7 (P = .0005 univariate analysis, P = .0004 multivariate analysis). The estimated percentage of patients relapse free 5 years after achieving a CR was 49% on HIDAC-3-7 and 24% on 7-3-7. Patients in CR tended to survive longer with HIDAC-3-7 but there were no overall survival differences between the two arms. HIDAC-3-7 was associated with significantly more toxicity in induction with more leukopenia, thrombocytopenia, nausea, and vomiting and eye toxicity (all P < .001) but a similar incidence of severe central nervous system and cerebellar toxicity compared to 7-3-7. The consolidation treatment was the same in both arms but caused significantly more leukopenia and thrombocytopenia in patients previously treated with HIDAC-3-7 induction (P < .0001). We conclude that a dose-effect exists for cytarabine in AML and that HIDAC-3-7 prolongs remission duration and disease-free survival and is tolerable when used as initial induction therapy in patients with de novo AML.

Acute Disease

Ultrastructural changes during adhesion and migration of pre-B lymphoid leukaemia cells within bone marrow stroma.

The ultrastructural changes in leukaemic cells on initial contact with, and during migration into, layers of bone marrow stroma in vitro were examined in a variety of types of acute leukaemia and leukaemic cell lines. Bone marrow fibroblasts (BMF) were grown on polycarbonate microporous membranes, and acute leukaemia cells added to cultures and allowed to adhere to BMF for variable periods of time before fixation. Acute lymphoblastic leukaemia (ALL) blasts showed rapid development of surface membrane microvilli on contact with BMF layers. ALL blasts, and the pre-B ALL cell line NALM-6, showed evidence of movement in to the BMF layer within 15-30 min, with intrusion of extended cytoplasic processes into gaps between BMF cytoplasm. ALL cells were frequently seen within the layers of fibroblasts after 30 min incubation, and had pronounced morphological changes, with pseudopodia and attenuated and elongated microvilli interdigitating with the surface of fibroblasts or with strands of extracellular matrix material. Changes were also noted in the surface membrane of BMF adjacent to ALL cells, with invagination of the cytoplasmic membrane and formation of micropits. In contrast to the migratory behaviour of pre-B ALL cells, migration was not observed with acute myeloid leukaemia cells or other leukaemic cell lines. These cells showed membrane activation, with variable degrees of microvillous formation, and in some cases insertion of pseudopodia into BMF layers, but migration was not observed. Ultrastructural immunogold labelling was carried out to determine the localization of leukaemic adhesion molecules and their ligands on BMF. This demonstrated that beta 1 integrins were largely localized to the contact surfaces of both ALL blasts and fibroblasts, with VCAM-1 expressed only on the surface of BMF. These observations confirm the specificity of migratory behaviour for pre-B leukaemic cells, and indicate that a complex pattern of surface and intracellular events mediate this process, including the expression of beta 1 integrins and VCAM-1 at the sites of insertion of leukaemic cells between fibroblast margins.

Acute Disease

Long-term survival and proliferation of precursor-B acute lymphoblastic leukemia cells on human bone marrow stroma.

Leukemic cells frequently persist in the bone marrow of patients treated for acute lymphoblastic leukemia (ALL), and may regrow to produce relapse. We have used a long-term co-culture system to analyze the interaction of ALL blasts with components of the marrow microenvironment. Blast cells from 10 cases of precursor-B ALL were cultured on allogeneic human bone marrow stromal layers at 37 degrees C in microtiter wells, and replated when stroma showed evidence of deterioration. Leukemic cells from seven of 10 cases showed evidence of survival and proliferation beyond 30 days in culture, while in three cases there was a progressive decline in the number of viable leukemic cells by 7-21 days. Two cases continued to proliferate for 149 to 332+ days, while five underwent senescence after 34-52 days. In the two cases with long-term proliferation, the leukemic identity of the cells was confirmed by immunophenotyping, cytogenetics, and demonstration of clonal immunoglobulin gene rearrangements. Evidence of selection of leukemic subclones was seen in two cases, with immumophenotypic evidence of loss of CD10 and CD34 antigens, and acquisition of CD20 and surface mu chain. The leukemic cells in these cases grew either in clumps attached to the surface of the stroma, or as'cobblestone areas' beneath the stromal cells. Survival and growth of two evaluable cases was dependent on the continuing presence of stromal cells in the culture system. In one case, direct contact with stroma was shown to be necessary to main- tain viability, while blast cells from the other case survived equally well when separated from the stroma by a 0.4-micron pore size microporous membrane. These results indicate that leu- kemic cells from the majority of cases of precursor-B ALL are able to persist and undergo proliferation in vitro in the presence of normal marrow stroma. This process appears dependent on either direct cell-cell contact, or on diffusible factors derived from the stroma. The availability of ALL cells capable of indefinite proliferation under these conditions will allow further analysis of the mechanisms mediating leukemic cell proliferation.

Adolescent

Prophylactic ganciclovir is more effective in HLA-identical family member marrow transplant recipients than in more heavily immune-suppressed HLA-identical unrelated donor marrow transplant recipients. Australasian Bone Marrow Transplant Study Group.

A multi-centre Australasian study of the efficacy of prophylactic ganciclovir in 88 recipients of marrow allografts at high risk for post-transplant cytomegalovirus (CMV) disease was conducted. The actuarial incidence of CMV disease was 10% in 74 recipients of HLA-identical family member transplants given ganciclovir but was 33% in 14 recipients of HLA-identical unrelated donor transplants given more immune-suppression pre- and post-transplant (P = 0.006). CMV disease developed in 4 of the 14 recipients of HLA-identical unrelated donor transplants at a median of 59 days post-transplant and was associated with concurrent graft-versus-host disease (GVHD) in 2 of the 4. CMV disease occurred in 5 of 74 recipients of an HLA-identical family member transplant at a median of 137 days post-transplant and was associated with concurrent moderate to severe GVHD in 4 of the 5. Thus the risk of CMV disease was higher in recipients who were not genotypically identical for HLA with their donors and who (in consequence) were given more immune-suppression than HLA-identical family member transplant recipients. Additionally, CMV disease can occur beyond the period of prophylactic ganciclovir administration (first 3 months post-transplant) in patients developing significant chronic GVHD and prophylaxis should be reintroduced at that time in such patients.

Adolescent

Filgrastim in patients with chemotherapy-induced febrile neutropenia. A double-blind, placebo-controlled trial.

OBJECTIVE: To determine if filgrastim (recombinant human methionyl granulocyte colony-stimulating factor) used in addition to standard inpatient antibiotic therapy accelerated recovery from infection associated with chemotherapy-induced neutropenia. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Hematology and oncology wards of four teaching hospitals. PATIENTS: 218 patients with cancer who had fever (temperature > 38.2 degrees C) and neutropenia (neutrophil count < 1.0 x 10(9)/L) after chemotherapy. INTERVENTION: Patients were randomly assigned to receive filgrastim (12 micrograms/kg of body weight per day) (n = 109) or placebo (n = 107) beginning within 12 hours of empiric therapy with tobramycin and piperacillin. Patients received treatment and remained in the study until the neutrophil count was greater than 0.5 x 10(9)/L and until 4 days without fever (temperature < 37.5 degrees C) had elapsed. MEASUREMENTS: Days of neutropenia and fever and days in the study (hospitalization); time to resolution of fever and febrile neutropenia; and frequency of the use of alternative antibiotics. RESULTS: Compared with placebo, filgrastim reduced the median number of days of neutropenia (3.0 compared with 4.0 days of a neutrophil count of < 0.5 x 10(9)/L; P = 0.005) and the time to resolution of febrile neutropenia (5.0 compared with 6.0 days; P = 0.01) but not days of fever (3.0 days for both groups). The frequency of the use of alternative antibiotics was similar in the two groups (46% compared with 41%; P = 0.48). The median number of days patients were hospitalized while on study was the same (8.0 days; P = 0.09); however, filgrastim decreased the risk for prolonged hospitalization (> 11 days, 4th quartile) by half (relative risk, 2.1 [95% CI, 1.1 to 4.1]; P = 0.02). In exploratory subset analyses, filgrastim appeared to provide the greatest benefit in patients with documented infection and in patients presenting with neutrophil counts of less than 0.1 x 10(9)/L. CONCLUSIONS: Filgrastim treatment used with antibiotics at the onset of febrile neutropenia in patients with cancer who have received chemotherapy accelerated neutrophil recovery and shortened the duration of febrile neutropenia.

Adolescent

Detection of intracellular lymphoid differentiation antigens by flow cytometry in acute lymphoblastic leukemia.

The value of flow cytometric detection of the intracellular lymphoid differentiation antigens CD3 and CD22 in the differential diagnosis of acute leukemia was assessed in cases of acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and leukemic cell lines. Cells were fixed in 0.25% paraformaldehyde at 4 degrees C for 60 min, permeabilized with 0.2% Tween 20 at 37 degrees C for 15 min, then stained with CD3 or CD22 monoclonal antibodies by indirect immunofluorescence. Cytoplasmic CD22 was detected on greater than 20% (mean 55%; range 20-87%) of blasts from all 20 cases of precursor-B ALL analyzed. The percentage of cells with cytoplasmic CD22 was greater than that with membrane CD22 in all except 2 cases of precursor-B ALL. Cytoplasmic CD22 was not detected in 8 cases of precursor-T ALL, 4 T-leukemia cell lines, or in 7 cases of AML. In contrast, cytoplasmic CD3 was detectable by flow cytometry in all 8 cases of precursor-T ALL, but not in precursor-B ALL, pre-B leukemia cell lines, or in AML. These results confirm that cytoplasmic CD3 and CD22 are excellent markers of the early T and B lineages in ALL and can be reliably detected by flow cytometry. This technique should be a valuable addition to routine immunophenotyping for classification of acute leukemia.

Antigens, CD

Prognostic value of immunophenotyping in acute myeloid leukemia. Australian Leukaemia Study Group.

The diagnostic and prognostic value of immunophenotyping with 18 murine monoclonal antibodies (MoAbs) to a variety of leukocyte differentiation antigens was assessed in 168 adults aged 15 to 60 years with acute myeloid leukemia (AML). Patients were entered on the multicentre Australian Leukaemia Study Group M4 protocol, and were randomized to receive either standard or high-dose Ara-C together with daunorubicin and etoposide as induction chemotherapy, followed by standard consolidation and maintenance therapy. Diagnostic bone marrow aspirate (152 cases) or peripheral blood samples (16) were analyzed by indirect immunofluorescence and flow cytometry. MoAbs used were directed at myeloid (CD11b, CD13, CD14, CD15, CD33, CD41), lymphoid (CD2, CD3, CD7, CD9, CD10, CD19), or stem cell (HLA-DR, CD34, c-kit receptor) antigens, as well as the leukocyte integrins CD18 and CD49e, and the transferrin receptor CD71. Of the myeloid markers, CD13 and CD33 were the most useful diagnostically (71% and 79% of cases positive, respectively), with CD11b, CD14, and CD15 less commonly positive. A minority of cases expressed lymphoid antigens, either T cell (CD2 16%, CD3 7%, CD7 28%) or B cell (CD10 2%, CD19 7%). CD34 was detected on 42% and c-kit receptor on 48%. When patients were analyzed for response to treatment, CD2, CD9, and CD14 were significantly associated with complete remission rate: cases expressing these antigens had a poorer response than negative cases. In univariate analysis, CD11b+ cases had shorter periods of remission (relative risk of relapse, 2.33; P = .003) and shorter survival (relative death rate, 1.91; P = .006). In multivariate analysis, adjusting for other prognostic factors, CD9 and CD11b were significantly predictive of shorter survival. No other marker had a significant predictive effect. We conclude that myeloid MoAbs are useful in confirming the diagnosis of AML, but their prognostic value may be limited to CD11b. Lymphoid antigen expression is a consistent phenomenon in a minority of cases of AML, but appears to have little clinical significance.

Acute Disease

Migration of acute lymphoblastic leukemia cells into human bone marrow stroma.

Most cases of acute lymphoblastic leukemia (ALL) arise from malignant transformation of B-cell precursors in the bone marrow. Recent studies have shown that normal and leukemic B-cell precursors bind to bone marrow stromal cells through the beta-1 integrins VLA-4 and VLA-5, thereby exposing early lymphoid cells to regulatory cytokines. It has been recently reported that the pre-B cell line NALM-6 is capable of migrating under layers of murine stromal cells in vitro (Miyake et al. J Cell Biol 1992;119:653-662). We have further analyzed leukemic cell motility using human bone marrow fibroblasts (BMF) as a stromal layer. The precursor-B ALL cell line NALM-6 rapidly adhered to BMF, and underwent migration or tunneling into BMF layers within 5 h, as demonstrated by light and electron microscopy, and confirmed by a chromium-labeling assay. Migration was also observed with the precursor-B ALL lines Reh and KM-3, with a T leukemia line RPMI-8402, the monocytic line U937, and the mature B line Daudi. In contrast, mature B (Raji), myeloid (K562, HL-60), and T lines (CCRF-CEM, MOLT-4) did not migrate. When cases of leukemia were analyzed, BMF migration was largely confined to precursor-B ALL, occurring in eight of 13 cases tested. Of other types of leukemia, migration was observed in one of four cases of T-ALL, but no evidence was seen in six acute myeloid leukemias and two patients with chronic lymphocytic leukemia. Only minimal migration into BMF was observed with purified sorted CD10+ CD19+ early B cells from normal adult marrow, while normal mature B lymphocytes from peripheral blood did not migrate. ALL migration was inhibited by monoclonal antibodies to the beta sub-unit of the VLA integrin family, and by a combination of antibodies to VLA-4 and VLA-5. Partial inhibition was also observed when leukemic cells were incubated with antibodies to VLA-4, VLA-5, or VLA-6 alone. In contrast, treatment of stromal cells with antibodies to vascular cell adhesion molecule or fibronectin (ligands of VLA-4 and VLA-5) did not prevent leukemic cell migration. These results indicate that ALL cells are highly motile and capable of rapid migration within marrow stroma, an effect largely mediated by VLA-4 and VLA-5. In the case of precursor-B ALL, this process may reflect a homing mechanism to areas of selective growth advantage within the bone marrow microenvironment.

Antigens, CD

Analysis of the mechanism of adhesion of precursor-B acute lymphoblastic leukemia cells to bone marrow fibroblasts.

Normal B lymphopoiesis is dependent on a close relationship between B-cell precursors and the bone marrow (BM) microenvironment. To further understand the mechanisms regulating the proliferation of the malignant counterpart of B-cell precursors, namely precursor-B acute lymphoblastic leukemia (ALL), we examined the adhesion to BM fibroblasts (BMF) of 19 cases of precursor-B ALL using a chromium labeling assay. Eleven of 19 cases showed greater than 10% binding to BMF (range 2.3% to 54.8%, mean 19.1%). Binding was increased approximately twofold by preincubation of BMF with tumor necrosis factor and interleukin-4, which also resulted in upregulation of expression of vascular cell adhesion molecule-1 (VCAM-1) on BMF. The mechanism of attachment was investigated using murine monoclonal antibodies to leukocyte integrins, principally the beta, integrins VLA-4 and VLA-5, which were demonstrated to be present on most cases by flow cytometry. Statistically significant inhibition of adhesion was observed with antibodies to the beta 1 common subunit, VLA-4, and VLA-5, whereas little effect was seen with antibodies to VLA-6 or the beta 2 integrin subunit. Preincubation of fibroblasts with an antibody to VCAM-1 (a ligand of VLA-4) inhibited leukemic cell binding in the majority of cases, which was an effect also observed on cytokine-stimulated BMF. However, a minority of cases, as well as the pre-B lines NALM-6 and KM-3, showed no evidence of inhibition of adhesion with anti-VCAM-1 antibodies. Treatment of BMF with antifibronectin antibody alone had little effect on ALL adhesion and did not enhance the inhibitory effect of anti-VCAM-1. These data indicate that precursor-B ALL cells bind to BM stroma through the beta 1 integrins VLA-4 and VLA-5 and that this effect is partly mediated by VCAM-1 on stromal cells, although other undefined VLA ligands are also likely to be involved. Attachment of ALL cells to stroma is likely to play a key role in regulating the survival and growth of these cells through exposure to stromal cytokines.

Adolescent

Geographical distribution of acute lymphoblastic leukaemia subtypes: second report of the collaborative group study.

Childhood acute lymphoblastic leukemia (ALL) T and B precursor subtypes have been identified by standardised immunophenotyping in different geographic and ethnic settings. Comparison of the relative frequencies and estimated incidence rates of the major subtypes indicates very similar values, with the striking exception of black childhood populations in Africa in which there appears to be a significant and selective deficit in the incidence of the common (B-cell precursor) subset of ALL. There is suggestive evidence for a similar bias in ALL subtypes in South Africans of mixed ethnic origin and in Mapuche Indians from Chile. Several interpretations of these data are possible but the one favoured attributes these differences primarily to socio-economic factors and patterns of infection in infancy.

Adolescent

Effects of interleukin 7 on the growth of clonogenic cells in T-cell acute lymphoblastic leukaemia.

The effects of the recombinant human cytokines interleukin 2 (IL-2) and IL-7 on the proliferation of T-acute lymphoblastic leukaemia (T-ALL) cells were tested in a clonogenic assay. Highly purified leukaemic cells were obtained by immunomagnetic depletion of mature T cells and fluorescence-activated cell sorting for immature leucocyte markers (CD1, CD10, CD34). Of 9 cases tested, only 3 showed evidence of stimulation by cytokines. One was stimulated by both IL-2 and IL-7, one by IL-2 only, and the third by IL-7 alone. A further case showed proliferation without addition of cytokines. The remaining 5 cases were completely unresponsive. While both IL-2 and IL-7 are capable of stimulating leukaemic cells from some cases of T-ALL, the molecules regulating the proliferation of T-ALL cells in vitro remain to be more fully elucidated.

Adolescent

GM-CSF after allogeneic bone marrow transplantation: accelerated recovery of neutrophils, monocytes and lymphocytes.

Ten patients given HLA-identical sibling marrow transplants for lymphoid malignancy received recombinant human granulocyte macrophage-colony stimulating factor (GM-CSF) from day 7 to day 13 inclusive post transplant. Patients were prepared for transplantation with busulphan 16 mg/kg and cyclophosphamide 120 mg/kg. Immunosuppression to minimise the risk of graft-versus-host disease (GVHD) was cyclosporin/short methotrexate. Results were compared with a historical control group of patients (n = 16) given matched sibling transplants for acute leukaemia and receiving the same immune suppressive regime but not given GM-CSF. Recovery of total white cells, neutrophils, monocytes and lymphocytes was more rapid in the GM-CSF recipients (p less than 0.02). There was a suggestion of a decrease in non-viral infections in the first 30 days in the GM-CSF recipients (p = 0.09). There was, however, no significant difference in the severity of oropharyngeal mucositis nor in the duration of the transplant hospitalisation. Surprisingly, the severity of acute GVHD was higher in the GM-CSF recipients with six of eight evaluable patients having grade II-IV acute GVHD (p = 0.003). Two GM-CSF recipients developed a fluid retention/capillary leak syndrome. These findings indicate a need for caution in the use of GM-CSF after allogeneic marrow transplantation.

Adolescent

Co-expression of haemopoietic antigens on vascular endothelial cells: a detailed phenotypic analysis.

Over 1000 monoclonal antibodies (MAB), previously characterized in terms of reactivity with various haemopoietic cells and including representatives from each of the currently known Clusters of Differentiation (CD), have now been evaluated by us for reactivity against human endothelial cells. In the current study, screening was performed on both fixed, and on non-fixed, endothelial cells derived and cultured from umbilical cord veins. Results indicate that endothelial cells co-express a wide variety of antigens that are otherwise characterized by expression on haemopoietic cells. The most intense and consistent degree of reactivity was seen using MAB to CD-9, CD-13, CD-29, CD-31, CD-44, CD-46, CD-51, CD-54 and CD-55, although reactivity was also observed using MAB belonging to CD-41, CD-47, CD-49, CD-61 and CD-71, in addition to a number of non-clustered MAB.

Antibodies, Monoclonal