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D C Linch

Publications and source records attributed to D C Linch.

At least 91 records · Page 5Linked to original sources
PubMed1997

Acquired skewing of X-chromosome inactivation patterns in myeloid cells of the elderly suggests stochastic clonal loss with age.

More frequent skewing of X-chromosome inactivation patterns (XCIPs) occurs in the white blood cells of elderly females; this study was performed to determine whether this occurs in myeloid or lymphoid lineages. XCIPs were analysed in purified neutrophils and T cells from 80 females > 75 years and the results were compared with 23 cord blood and 94 younger adult blood samples. The degree of XCIP skewing in cord blood and younger adult blood cells was similar, with 3-4% having > 90% expression of one allele. Skewing was markedly increased in the neutrophils of elderly females, with 33% having > 90% expression of one allele (P < 0.0001). Extreme skewing was present in only 9% of the elderly T-cell samples and no evidence of T-cell clonality was found by PCR analysis of the TCR gamma gene. The high level of acquired skewing of the XCIPs in myeloid cells of the elderly suggests that with time there is a change in stem cell usage with stochastic loss of some of the original stem cells. This has major implications for the use of XCIP analysis in the diagnosis of myeloid malignancies in the elderly and for gene therapy into haemopoietic stem cells.

Adolescent↗
PubMed1997

Granulocyte-macrophage colony stimulating factor receptor alpha and beta chain complexes can form both high and intermediate affinity functional receptors.

Scatchard analysis of primary human haemopoietic cells using iodinated GM-CSF suggests that there are low, intermediate and high affinity classes of the GM-CSF receptor. To investigate the molecular basis of this, we generated a clone of transfected NIH3T3 cells that constitutively expressed the human granulocyte-macrophage colony stimulating factor receptor (GM-CSF R) beta chain and inducibly expressed the human GM-CSF R alpha chain. In the cells fully induced to express the alpha chain the overall level of expression of the alpha and beta chains at the cell surface was comparable with that found in primary haemopoietic cells and cell lines. When cells were partially induced to express the alpha chain, the alpha:beta ratio determined by antibody binding was approximately 1:1 and Scatchard analysis revealed a single class of intermediate affinity receptors (Kd = 614+/-88 pM). In cells with fully induced alpha chain expression, the alpha:beta ratio was approximately 3:1 and there was a switch to a dual high and low affinity receptor with K(d)s of 67+/-32 pM and 1.7+/-0.56 nM respectively. The change from intermediate to high affinity was not associated with changes in alphabeta stoichiometry as detected by cross-linking with radiolabelled GM-CSF and gel electrophoresis. Both the high and intermediate affinity receptors were able to activate the STAT 5 and the MAP kinase pathways, although there was a difference in the ligand dose-response curves which was compatible with the different affinities of the receptors. It is proposed that the switch from an intermediate to high affinity receptor was due to the availability of free alpha chains presenting ligand to the alphabeta chain complexes at the surface of the cell membrane.

3T3 Cells↗
PubMed1997

Incidence of AML1/ETO fusion transcripts in patients entered into the MRC AML trials. MRC Adult Leukaemia Working Party.

Acute myeloid leukaemia (AML) with the t(8;21)(q22;q22) is deemed to be a 'good-risk' disease. 396 patients with AML at diagnosis were screened for the presence of t(8;21) and AML1/ETO fusion transcripts by cytogenetic and RT-PCR techniques respectively. 32 cases of t(8;21) were detected, all of which were also PCR positive. A further 19 cases were detected at the molecular level, predominantly but not exclusively in M1 and M2 FAB types. Approximately 12% of all new cases of AML are estimated to have AML1/ETO fusion transcripts and it is suggested that molecular screening should be performed in all cases with the possible exception of the M3 FAB type.

Acute Disease↗
PubMed1997

The clinical outcome of 65 cases of mantle cell lymphoma initially treated with non-intensive therapy by the British National Lymphoma Investigation Group.

Mantle cell lymphoma (MCL) was first described as a distinct biological entity on the basis of its association with the t(11;14)(q13;q32) resulting in over-expression of the cyclin D1 gene. Recognition of the morphological, immunophenotypic and clinical characteristics of MCL has enabled the accurate diagnosis of this entity and appreciation of its poor prognosis. Most published series of patients with MCL have used anthracycline-containing regimens. In contrast the British National Lymphoma Investigation (BNLI) group have treated 65 patients with MCL with non-intensive 'low-grade lymphoma' therapy. The median overall survival of 57 months and progression-free survival of 24 months compares favourably with the more intensively treated series. Although the disease was generally more aggressive than other low-grade lymphomas, some patients were asymptomatic and had indolent disease. When compared to 1853 patients with non-MCL low-grade lymphomas entered on the BNLI database, patients were found on average to be older (P=0.02), to have more extranodal disease (P<0.00001), and a higher proportion to have a raised ESR (P=0.02) and a low serum albumin (P=0.002). Multivariate analysis of significant prognostic markers in all BNLI low-grade lymphomas failed to identify MCL as an independent prognostic factor.

Adult↗
PubMed1997

G-CSF after peripheral blood stem cell transplantation in lymphoma patients significantly accelerated neutrophil recovery and shortened time in hospital: results of a randomized BNLI trial.

We have undertaken a prospective randomized study in 90 patients with relapsed or resistant lymphomas to assess the value of G-CSF (lenograstim) in the acceleration of myeloid recovery after peripheral blood stem cell transplantation (PBSCT). A common regimen of cyclophosphamide 1.5 g/m2 on day 1 and lenograstim 263 microg s.c. on days 2-10 with two aphereses on days 10 and 11 was used for stem cell mobilization. 77% of patients achieved an adequate PBSC collection in two harvests (> 2 x 10(8) MNC/kg or > 2 x 10(6) CD34+ cells/kg). 65 patients went on to receive high-dose BEAM chemotherapy and engraftment data was available for 62. 34 patients had been randomized to receive lenograstim 263 microg/d s.c. and 28 to no growth factor. The median time to ANC > 0.5 x 10(9)/l was 9 d in the lenograstim arm versus 12.5 d in the no-lenograstim arm (P=0.0001). This was associated with a median duration of time in hospital post PBSCT of 13 d in the lenograstim arm versus 15.5 d in the no-lenograstim arm (P=0.0002). Median days to platelet independence, platelet transfusions, incidence of infection and red cell transfusion were the same in both arms. These data indicate that lenograstim significantly accelerated myeloid recovery after PBSCT and shortened the duration of hospital stay.

Adult↗
PubMed1997

The predominant E2F complex in human primary haemopoietic cells and in AML blasts contains E2F-4, DP-1 and p130.

The E2F family of transcription factors are thought to play an important role in the control of cell cycle progression. There is now also increasing evidence that some family members may act as oncogenes or tumour suppressor genes. The characterization of these proteins in human primary haemopoietic cells and acute myeloid leukaemia (AML) blasts may thus give an insight to the molecular mechanisms governing proliferation and leukaemogenesis in these cells. Therefore we analysed the expression of E2F-DNA binding activity and the constituent proteins found in the complexes in human primary haemopoietic cells of various lineages. We also studied blasts from 18 patients with acute myeloid leukaemia (AML). On electromobility shift assays (EMSA) a single E2F-DNA binding complex was detected in T cells, B cells and monocytes which was shown to contain E2F-4, DP-1 and p130, indicating that all quiescent haemopoietic cells have the same complex. Examination of 18 AML samples by EMSA revealed the presence of E2F binding and no gross abnormalities were detected. An E2F-4/p130 complex was detected in representative samples of all FAB types analysed. Thus abnormalities of E2F function are unlikely to play a primary pathogenic role in AML.

Blotting, Western↗
PubMed1997

Frequency of CBF beta/MYH11 fusion transcripts in patients entered into the U.K. MRC AML trials. The MRC Adult Leukaemia Working Party.

It has been established that cytogenetic findings at diagnosis of acute myeloid leukaemia (AML) are a powerful prognostic indicator. Patients who have the inv(16)(p13q22), closely associated with the FAB subtype M4Eo. are deemed to have good-risk disease. This subtle translocation may be difficult to detect in poor-quality metaphase preparations and if missed could lead to the incorrect assignment of risk group and influence further treatment strategies. We studied 321 patients with AML at diagnosis for the presence of inv(16)(p13q22) and CBF beta/MYH11 fusion transcripts by cytogenetic and RT-PCR techniques respectively. Karyotypic analysis detected 21 cases of inv(16) (p13q22), all of which were PCR positive. A further 12 cases were detected at the molecular level only, in FAB types other than M4Eo. The observed frequencies of CBF beta/MYH11 fusion transcripts in our study have been adjusted for the reported incidence of each FAB subtype and we calculate that 10.1% of all new cases of AMLs have molecular evidence of inv(16)(p13q22). only half of which are of the M4Eo subtype. We conclude that molecular screening for the presence of CBF beta/MYH11 fusion transcripts should be mandatory in all case of AML at diagnosis.

Adolescent↗
PubMed1997

Peripheral blood stem cell transplantation.

High dose chemo/radiotherapy requiring autologous haemopoietic stem cell support is increasingly used in a variety of malignant disorders. Mobilised peripheral blood stem cells (PBSC) have largely replaced the use of autologous bone marrow due to more rapid haemopoietic reconstitution with less resource use including blood and platelet transfusion requirements. PBSC graft adequacy is monitored by CD34+ cell and granulocyte-monocyte-colony-forming-cell measurements, and thresholds for rapid engraftment have been determined. Studies are in progress to determine the optimal mobilisation regimens that will permit the achievement of the necessary progenitor thresholds with only one or two aphereses. This will facilitate the use of multiple cycles of high dose therapy and possibly the use of PBSC collected by venesection rather than apheresis. PBSC are also increasingly used in the allogeneic setting where specific mobilisation protocols not using cytotoxic drugs are employed. These technical advances will aid the execution of large trials to determine the efficacy of high dose therapy.

Blood Specimen Collection↗
PubMed1997

Economic analysis of a randomized clinical trial to compare filgrastim-mobilized peripheral-blood progenitor-cell transplantation and autologous bone marrow transplantation in patients with Hodgkin's and non-Hodgkin's lymphoma.

PURPOSE: High-dose chemotherapy (HDC) with peripheral-blood progenitor cell (PBPC) and autologous bone marrow (ABM) transplant (T) has documented survival benefits for relapsed Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). Treatment costs associated with HDC and its supportive care have restricted its use both on and off clinical trial. In a prospective randomized clinical trial, filgrastim-mobilized PBPCT resulted in faster recovery of bone marrow function, with less hospitalization and supportive care than ABMT. This study was undertaken to analyze the costs of the two strategies using prospectively collected data from a randomized clinical trial that compared filgrastim-mobilized PBPCT versus ABMT. PATIENTS AND METHODS: Clinical results and resource utilization from a randomized clinical trial that compared filgrastim-mobilized PBPCT versus ABMT following carmustine, etoposide, cytarabine, and melphalan (BEAM) HDC for HD and NHL are presented. The trial was performed in six centers in Germany, the United Kingdom, and Belgium. Resource utilization data were used to project costs and Massay Cancer Center (MCC) in the United States incurred the cost of treating the cohort. Costs were projected to the United States, because the economic implications to United States centers are significant, costs of care vary markedly among countries but resource utilization on this trial did not, and a randomized trial is unlikely to be performed in the United States. RESULTS: Fifty-eight patients with relapsed HD or NHL underwent HDC with BEAM. The PBPCT and ABMT groups had similar short-term survival after BEAM. PBPCT patients had a shorter hospitalization (median, 17 v 23 days; P = .002), neutrophil recovery (11 v 14 days; P = .005), platelet recovery to > or = 20 x 10(9)/L (16 v 23 days; P = .02), and days of platelet transfusions (6 v 10; P < .001). Estimated costs were $8,531 for ABM harvest and $5,760 for PBPC collection, including filgrastim mobilization. The total estimated average cost was $59,314 for each ABMT patient versus $45,792 for each PBPCT patient. Cost savings of $13,521 (23%) were due to shorter hospitalizations with less supportive care. CONCLUSION: PBPCT is as safe and more effective than ABMT for HD and NHL in the short term. PBPCT represents a significant cost savings due to lower autograft collection costs, shorter hospital stays, and less supportive care. The savings exceed the costs for filgrastim mobilization and PBPC collection. Actual savings will vary depending on local practice patterns, charges, and costs.

Adolescent↗
PubMed1997

Progenitor-cell mobilization after low-dose cyclophosphamide and granulocyte colony-stimulating factor: an analysis of progenitor-cell quantity and quality and factors predicting for these parameters in 101 pretreated patients with malignant lymphoma.

PURPOSE: To define parameters that predict for rapid engraftment after peripheral-blood stem-cell (PBSC) transplantation, progenitor thresholds, the proportion of patients who achieve these thresholds with a standardized mobilization regimen, and the factors that predict for mobilization efficiency. PATIENTS AND METHODS: One hundred and one patients with pretreated lymphoma were mobilized with cyclophosphamide 1.5 g/m2 and granulocyte colony-stimulating factor (G-CSF), with the first apheresis performed when the recovery WBC count was > or = 5.0 x 10(9)/L. The relationship between the number of progenitor cells collected and patient age, sex, diagnosis, prior radiotherapy, and time since last chemotherapy was determined by multivariate analysis. The relationship between these factors, progenitor numbers returned, post-PBSC G-CSF, and hematologic recovery was performed in 81 patients following chemotherapy with carmustine (BCNU), etoposide, cytarabine, and melphalan (BEAM protocol). RESULTS: No BEAM recipients had delayed neutrophil recovery beyond 28 days. Delayed platelet recovery occurred in 7.4% and minimum and optimum thresholds of 1 x 10(6) and 3.5 x 10(6) CD34+ cells/kg and 1 x 10(5) and 3.5 x 10(5) granulocyte-macrophage colony-forming cells (GM-CFC)/kg were established. Hematologic recovery was adversely affected by prior treatment with mini-BEAM, and neutrophil recovery was accelerated by post-PBSC G-CSF. The minimum GM-CFC threshold was achieved with a single apheresis in 83% of patients and in 90% with two aphereses. The optimal threshold was achieved with two leukaphereses in 69% of patients. Prior radiotherapy adversely affected mobilization. CONCLUSION: Hematopoietic recovery following PBSC is dependent on progenitor-cell number infused and affect of previous chemotherapy on progenitor quality. Progenitor-cell mobilization is adversely affected by prior radiotherapy. The minimum threshold of GM-CFC required is achieved in most patients with a single apheresis, but an optimal collection usually requires at least two harvests.

Adolescent↗
PubMed1997

Analysis of the coding sequence for the GM-CSF receptor alpha and beta chains in patients with juvenile chronic myeloid leukemia (JCML).

Peripheral blood granulocyte-macrophage progenitors (CFU-GMs) from patients with juvenile chronic myeloid leukemia (JCML) are able to proliferate spontaneously in the absence of exogenous growth factors and studies have shown that these progenitors display a hypersensitive growth response to GM-colony-stimulating factors (CSFs) in culture. We screened RNA from six patients with JCML for mutations in the GM-CSF receptor (GM-CSFR) coding sequence using RT-PCR-SSCP. Altered patterns were found in five patients for the GM-CSFR alpha chain, and in five patients for the beta chain. Two nucleotide substitutions accounted for all alpha chain abnormalities; one was conservative for Val333 and the other caused an Ala17-->Gly substitution. Both had previously been detected in normal controls. Sequencing of beta chain abnormalities revealed four base substitutions. Three were previously described polymorphisms, one causing a Pro603-->Thr substitution and two conservative point mutations involving Ser426 and Pro648. A further nucleotide mutation, which resulted in a Glu249-->Gln substitution, was also found but is not thought to be of pathological significance. Polymorphisms of the GM-CSFR alpha and beta chains are common, but pathogenic point mutations of the GM-CSFR are infrequent in patients with JCML and are unlikely to be involved in the hypersensitivity to GM-CSF demonstrated by progenitor cells.

Humans↗
PubMed1997

Impact of high-dose salvage therapy (BEAM) on overall survival in younger patients with advanced large-cell lymphomas entered into BNLI trials.

The survival of two cohorts of patients with stage III/IV large-cell lymphomas treated by CHOP has been compared. In the first cohort of 88 patients (1974-1982), high-dose therapy with autologous bone marrow transplantation (ABMT) was not available as salvage therapy and in the second cohort of 87 patients (1987-1992), this was the recommended salvage for patients with disease that was still chemosensitive to conventional-dose therapy. The actuarial overall survivals at five years were 40% and 44% in the first and second cohorts, respectively, indicating that the availability of ABMT had made little impact. Of the 62 patients in the second cohort who failed CHOP therapy, 8 died before second-line chemotherapy could be given, 1 refused more therapy, and 8 were considered unsuitable for further combination chemotherapy. Seven patients with localized disease remaining received local radiotherapy. Of the 38 patients given salvage therapy, 14 had chemoresistant disease. Only 9 patients received high-dose BEAM chemotherapy and ABMT, and 7 remain disease-free. ABMT was restricted to a highly select patient group, and as a result more widespread application of this strategy might result in only a modest further improvement.

Adolescent↗
PubMed1997

The effects of human macrophage inflammatory protein-1 alpha and its genetically modified variant, BB10010, on phagocyte function.

BB-10010 is a genetically modified form of human macrophage inflammatory protein-1 alpha (MIP-1 alpha) with a single amino acid substitution of Asp26 by alanine, which inhibits aggregation of the native molecule. BB-10010 has stem cell protective properties, and has entered clinical trials for this purpose. The aim of this study was to determine the effects of BB-10010 on human phagocyte function and compare them with the native molecule. MIP-1 alpha and BB-10010 had identical dose-response curves in assays of calcium mobilization; however, neutrophils were less sensitive than monocytes to either MIP-1 alpha form, suggesting differences in receptor expression. Neither MIP-1 alpha type directly stimulated phagocyte superoxide production, nor did it have any priming effect on agonist-induced superoxide production. Both MIP-1 alpha and BB-10010 enhanced monocyte migration; however, cells were more sensitive to the native molecule, with optimal effects seen at 1 ng/ml compared with 100 ng/ml BB-10010. Concomitant alteration of CD11b, CD18, and CD49d (VLA-alpha 4) cell adhesion molecule expression was not seen with either MIP-1 alpha type. With the exception of the difference in monocyte sensitivity in chemotaxis assays, BB-10010 reproduces the effects of the native molecule on phagocytes. BB-10010 does not have proinflammatory effects on neutrophil activation, and this bodes well for its clinical use.

Calcium↗
PubMed1996

Prognostic significance of BCL-2 expression and bcl-2 major breakpoint region rearrangement in diffuse large cell non-Hodgkin's lymphoma: a British National Lymphoma Investigation Study.

The Bcl-2 protein is capable of preventing apoptosis, and in vitro evidence suggests a role in drug resistance. It is expressed and the gene is rearranged in a proportion of cases of large-cell non-Hodgkin's lymphoma (NHL), but the clinical significance of these findings is controversial. The purpose of this study was to determine the influence of both Bcl-2 expression and major breakpoint region (MBR) bcl-2 rearrangement in a large cohort of prospectively accrued patients with intermediate-grade B-cell NHL treated in a standardized manner. All patients with Working Formulation F, G, or H NHL treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy in British National Lymphoma investigation studies between July 1974 and April 1992 were considered for this study if the appropriate paraffin blocks were available. Paraffin sections from the diagnostic specimen were analyzed for evidence of MBR rearrangement using a polymerase chain reaction-based method, and for Bcl-2 expression using immunohistochemistry. Failure to achieve complete remission (CR), relapse, death from NHL, and deaths from all causes were used as end points to measure CR rate, actuarial relapse rate, actuarial survival from NHL, and actuarial overall survival. One hundred sixty-one suitable patients were identified and tested for the bcl-2 MBR translocation, with 27 (17%) found to be positive; 153 of these patients were tested with immunocytochemistry, and 84 (55%) showed evidence of Bcl-2 expression. For patients who achieved CR from the initial treatment, the relapse rate was significantly higher in those with Bcl-2 expression than in those without. In addition, multivariate analysis identified Bcl-2 expression as the only factor significantly related to relapse rate in the subjects measured. The cause-specific survival for NHL in the series as a whole was significantly lower in patients with Bcl-2 expression than in those without. MBR status had no significant influence on any of the outcome measures, but the number of MBR-positive patients was relatively small, and larger studies are required. In conclusion, in Working Formulation F, G, and H NHL of B-cell type, expression of Bcl-2 protein predicted independently for relapse.

Adult↗
PubMed1996

Randomised trial of filgrastim-mobilised peripheral blood progenitor cell transplantation versus autologous bone-marrow transplantation in lymphoma patients.

BACKGROUND: A randomised trial comparing filgrastim-mobilised peripheral blood progenitor cell (PBPC) transplants with autologous bone marrow transplantation (ABMT) for haematopoietic stem cell support has not been done. We compared the effects of filgrastim-mobilised PBPC or autologous bone marrow reinfused to lymphoma patients after high-dose chemotherapy in a prospective randomised multicentre trial. METHODS: The trial was done at six centres in three European countries. After high-dose chemotherapy (carmustine, etoposide, cytarabine, and melphalan [BEAM protocol]) 58 patients with advanced Hodgkin's disease or high-grade non-Hodgkin lymphoma received either filgrastim-mobilised PBPC (n = 27) or bone marrow (n = 31) for haemopoietic reconstitution. FINDINGS: The median number of days with platelet transfusions after grafting was 6 in the PBPC transplantation group and 10 in the ABMT group (estimate of treatment difference 5 days, 95% CI 3-7 days). Time to platelet recovery above 20 x 10(9)/L was 16 days in the PBPC transplantation group and 23 days in the ABMT group (p = 0.02). Time to neutrophil recovery above 0.5 x 10(9)/L was also reduced in the PBPC transplantation group (11 vs 14 days, p = 0.005). Patients randomised to PBPC transplantation needed fewer red blood cell transfusions (two vs three, p = 0.002) and spent less time in hospital (17 vs 23 days, p = 0.002). Early post-transplant morbidity and mortality as well as overall survival (median follow-up 311 days) were similar in both groups. There was no notable toxicity ascribed to filgrastim administration or the leucapheresis procedures. INTERPRETATION: In patients with lymphoma treated with high-dose chemotherapy, reinfusing filgrastim-mobilised PBPC instead of autologous bone marrow significantly reduced the number of platelet transfusions, the time to platelet and neutrophil recovery, and led to earlier discharge from hospital.

Adult↗
PubMed1996

Management of the histologically aggressive non-Hodgkin's lymphomas in adults.

The understanding of lymphocyte biology and lymphomagenesis has increased dramatically in the past two decades, but this has not been matched by rapid advances in therapy. There have been numerous false dawns and these serve to emphasize the importance of large randomized trials. Increasingly, therapy must be designed for specific subgroups of patients, this making it difficult to perform large trials and accentuating the need for multicentre collaboration.

Adult↗
PubMed1996

A randomised comparison of a third-generation regimen (PACEBOM) with a standard regimen (CHOP) in patients with histologically aggressive non-Hodgkin's lymphoma: a British National Lymphoma Investigation report.

A combination of cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) has been a standard therapy for histologically aggressive non-Hodgkin's lymphomas for over 20 years, but several newer regimens, referred to as second or third generation, have been reported to give improved results in single-centre studies. Positive evidence from randomised trials has been lacking, and the British National Lymphoma Investigation therefore commenced a randomised comparison of CHOP vs a third-generation regimen, PACEBOM, in November 1987. A total of 459 eligible patients were entered into the trial: 226 in the CHOP arm and 233 in the PACEBOM arm. Overall, there was no significant difference in outcome between the two arms of the trial. In patients with stage IV disease there was an apparent improvement in survival for those treated with PACEBOM, but considerable caution must be exercised with such subgroup analysis.

Aged↗