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N H Russell

Publications and source records attributed to N H Russell.

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

Bcl-2 expression in acute myeloblastic leukaemia: relationship with autonomous growth and CD34 antigen expression.

The bcl-2 gene encodes a mitochondrial protein that inhibits the onset of apoptosis induced by growth factor withdrawal or cytotoxic agents. Using quantitative flow cytometry and expressing bcl-2 levels as the number of molecules of equivalent soluble fluorochrome (MESF) per cell, we have shown that bcl-2 protein expression in the blast cells from patients with acute myeloblastic leukaemia (AML) is heterogeneous, but not related to FAB type. The blast cells from AML patients with the capacity to grow and survive autonomously in vitro were found to have higher bcl-2 MESF values than those that were dependent upon exogenous growth factors. We have previously reported that the blast cells from 70% of AML patients exhibit autonomous growth and autocrine growth factor production in vitro and that this has been shown to be an important indicator of poor prognosis in AML. High bcl-2 expression has also been associated with a low complete remission rate and poor survival in AML. In the patients whose blast cells exhibited autonomous growth, neutralisation of endogenous GM-CSF resulted in down-regulation of bcl-2 protein, whereas in blast cells from patients whose cells proliferated only in the presence of added growth factors, incorporation of recombinant human (rh) GM-CSF in the culture media resulted in up-regulation of bcl-2. Because CD34 positivity has been reported as another indicator of poor prognosis in AML, we compared bcl-2 expression in cases of CD34 positive AML, CD34 negative AML and CD34 positive normal bone marrow cells. Bcl-2 was found to be strongly expressed on the CD34+ normal bone marrow cells. The blast cells from CD34+ AML patients expressed significantly higher bcl-2 levels than CD34- AML patients. In five cases of CD34+ AML, the bcl-2 levels were determined on purified CD34+ and CD34- blast cell populations. The CD34+ blast cells were found to express significantly higher bcl-2 levels compared with the CD34-blast cells. Our data would suggest that quantification of bcl-2 in AML blast cell may be useful as a prognostic indicator in AML.

Acute Disease↗
PubMed1996

Down-regulation of bcl-2 in AML blasts by all-trans retinoic acid and its relationship to CD34 antigen expression.

High levels of expression of the bcl-2 oncoprotein in acute myeloblastic leukaemia (AML) cells have been associated with low complete remission rates and poor survival. The sensitivity of AML blasts to drugs such as Ara-C can be increased by the down-regulation of bcl-2 expression by antisense oligonucleotides. All-trans retinoic acid (ATRA) has been reported to increase the sensitivity of AML cell lines to Ara-C and to induce differentiation in the HL60 promyelocytic cell line, with both effects being accompanied by a decrease in bcl-2 expression. Using flow cytometry and a monoclonal antibody to bcl-2, we have investigated the effects of ATRA (1 microM) on bcl-2 expression in the blast cells of 25 AML patients and the K562 cell line after incubation for 72 or 24 h, respectively. Using Kolmogorov-Smirnov statistical analysis where a D value of > 0.12 was statistically significant, we found that in 8/25 AML samples and the K562 cells there was a significant decrease in bcl-2 protein expression after incubation with ATRA (D value range 0.14-0.44). The mean peak fluorescence (MPF) values for the bcl-2 levels of the ATRA responders (n = 8) was reduced to 35.5 +/- 6.9 following incubation with ATRA compared to 47.6 +/- 8.2 (mean +/- SEM) for control samples incubated in the absence of ATRA (P = 0.014). There was no significant difference between the baseline bcl-2 molecules of equivalent soluble fluorochrome (MESF) levels in the ATRA responders (48.9 +/- 5.7, n = 8) and the non-responders (41.3 +/- 3.9, n = 17) (mean +/- SEM) (P = 0.28). The down-regulation of bcl-2 expression by ATRA was particularly associated with CD34-negative AML and of the eight AML patients' cells that responded to ATRA by down-regulating bcl-2, seven were CD34 negative (P < 0.05). Our data suggest that the addition of ATRA to combination chemotherapy would increase the chemosensitivity of some patients with AML, particularly CD34-negative AML, due to down-regulation of bcl-2 expression.

Antigens, CD34↗
PubMed1996

Detection of clonal immunoglobulin gene rearrangements in the peripheral blood progenitor cells of patients with multiple myeloma: the potential role of purging with CD34 positive selection.

Aims-To determine the extent of clonal cell contamination of peripheral blood progenitor cell (PBPC) collections in patients with multiple myeloma (MM) and to assess the purging efficacy of CD34 positive selection.Methods-PBPC collections from 29 patients with MM were analysed for the presence of clonal immunoglobulin heavy chain (IgH) gene rearrangements with a fluorescence based PCR technique. In addition, the PBPC from eight of the 29 patients were "purged" by selection of CD34 positive haematopoietic progenitors with an avidin-biotin immunoabsorption column (Ceprate). In each case the unmanipulated PBPC, CD34 positive and waste fractions were all assessed for the presence of clonal IgH rearrangements.Results-Clonal IgH rearrangements (identical with those demonstrated in diagnostic bone marrow samples) were demonstrated in 10 (35%) of 29 cases and seemed to be confined to those with significant residual bone marrow disease. Clonal rearrangements were evident in the PBPC of two of the eight patients who underwent CD34 selection; in both instances a "clonal purge" was seen as it was not possible to demonstrate the clonal rearrangement in the CD34 positive fraction. In four of the six remaining cases the normal polyclonal fingerprint could not be demonstrated in the CD34 positive fraction, which is consistent with a significant reduction in contaminating B cells.Conclusions-Clonal cells contaminate PBPC collections in a significant proportion of patients with MM and may be eliminated by CD34 positive selection.

Journal Article↗
PubMed1995

Primary transplantation of allogeneic peripheral blood progenitor cells mobilized by filgrastim (granulocyte colony-stimulating factor)

Transplantation of allogeneic peripheral blood progenitor cells (PBPCs) may have advantages over bone marrow transplantation (BMT) with regards to the speed of hematopoietic and immunologic recovery, which may then shorten the time spent in hospital and decrease costs. The recipient might also profit by an enhanced graft-versus-leukemia reaction exerted by the high number of natural killer cells contained in such grafts. The donor could be spared the discomfort and risks of general anesthesia and marrow harvesting. Primary transplantation of unmanipulated allogeneic PBPCs has not been reported so far because the vast amount of T cells contained in the collection product was thought to cause severe graft-versus-host disease. We present preliminary data on primary transplantation of allogeneic PBPCs in patients who either suffered from advanced leukemia or had a donor unable to undergo general anesthesia. Eight patients with a median age of 42 years suffering from acute myelogenous leukemia (AML) in first remission (n = 3), AML in third remission, AML in relapse (n = 2), acute lymphoblastic leukemia in second remission, or chronic myelogenous leukemia in accelerated phase received myeloablative therapy followed by transplantation of unmanipulated allogeneic PBPCs mobilized with granulocyte colony-stimulating factor (5 to 10 micrograms/kg of body weight of filgrastim administered for 5 to 6 days) in their HLA-identical donors. Hematopoietic reconstitution was achieved in all patients with a median of 15.5 (16.5) days after transplant needed to surpass an absolute neutrophil count of 0.5 (1.0) x 10(9)/L. The median time to an unsupported platelet count greater than 20 (> 50) x 10(9)/L was 19.5 (41) days after grafting. Three patients did not exhibit signs of acute graft-versus-host disease (GVHD), grade I disease was seen in one patient, and three patients experienced grade II disease limited to the skin. The only patient with severe acute GVHD (grade III) refused to take his oral cyclosporin regularly and had ineffective serum levels for most of the time until relapse. Six of eight patients are currently alive without evidence of disease between 61 and 533 days after grafting; two patients grafted for AML in relapse achieved a complete remission after transplantation but relapsed again and died of leukemia on days +48 and +70, respectively. Primary transplantation of unmanipulated allogeneic PBPCs is feasible and results in long-term engraftment without causing detrimental GVHD.

Adolescent↗
PubMed1995

Bone marrow transplantation: current situation, complications and prevention.

The number of patients undergoing BMT is rising steadily. The increase is due to a broadening of the indications for transplantation and an increase in the donor pool. There has been a progressive improvement in outcome particularly due to a fall in transplant-related mortality. Methotrexate and cyclosporin are the mainstay of graft versus host disease (GVHD) prophylaxis, but acute GVHD remains a major problem in the unrelated donor recipient. Infections remain an important cause of death and emphasise the crucial role of antimicrobial prophylaxis; death from Gram-negative sepsis has been significantly reduced by the use of prophylactic antibiotics. Fungal infections carry a high mortality, especially in allogenic transplant recipients. Fluconazole is used to protect patients in the neutropenic period and beyond in higher risk individuals. Viral infections, which may occur late, are emerging as a significant cause of morbidity and mortality in the allogeneic, particularly unrelated transplantation setting. A long term susceptibility to encapsulated bacteria suggests delayed immune reconstitution; revaccination policies are standard in most units. The longer term effects of transplantation are increasingly important with improving survival and include chronic GVHD, endocrine, cardiorespiratory and other systemic abnormalities. The increased risk of secondary malignancies is also of concern.

Adolescent↗
PubMed1995

Blood stem cell allografting.

The emergence of peripheral blood stem cells as the preferred source of autologous rescue in high-dose therapy has indicated their potential benefits for allogeneic transplantation. Adequate mobilization with minimal side-effects can be achieved in normal donors using a short course of G-CSF. Allogeneic stem cells provide long-term engraftment that appears to be more rapid than that seen with marrow, but this observation awaits confirmation in a prospective randomized study. The cellular composition of stem cell and bone marrow allografts is very different, with greater numbers of CD34+ progenitors, T lymphocytes, and natural killer cells in stem cell harvests. Although infused T-cell numbers are increased, no difference in acute graft-versus-host disease has been documented between stem cell and marrow allografts. Any differences in chronic graft-versus-host disease or relapse risk await longer follow-up. It is likely that the use of allogeneic stem cells will expand both in matched sibling and mismatched transplantation.

Graft vs Host Disease↗
PubMed1995

Comparative quantitative expression of bcl-2 by normal and leukaemic myeloid cells.

Expression of the bcl-2 oncoprotein by AML blasts has previously been demonstrated to be heterogenous with high levels of bcl-2 expression being associated with a low complete remission rate and poor survival. We have quantified bcl-2 expression in AML blasts in relation to expression of the CD34 antigen and in comparison to CD34-positive cells from normal bone marrow. When expressed as molecules of equivalent soluble fluorochrome (MESF) per cell. AML blast cell bcl-2 expression varied from 11.1 to 99.9 x 10(3) (median 39.4 x 10(3), n = 56) with 28.5% of patients expressing high MESF values (> 50 x 10(3)) and 16% of patients expressing low MESF values (< 20 x 10(3), the remainder expressing intermediate values. There was no significant difference between intensity of bcl-2 expression and FAB classification in the de novo AML cases; and there was no significant differences between de novo and secondary AML cases. Blasts from CD34+ AML patients expressed significantly higher levels of bcl-2 (mean MESF 43.6 x 10(3), n = 36) than CD34- AML patients (mean MESF 31.7 x 10(3), n = 19). In five cases of CD34+ AML, bcl-2 expression was determined on purified CD34+ and CD34- blast cell populations. In all cases CD34+ blasts were found to express significantly higher bcl-2 MESF values compared to the CD34- fraction. Purified CD34+ cells from normal bone marrow consistently expressed high levels of bcl-2 (MESF > 75 x 10(3), n = 4), which was comparable to that found on CD34+ AML cells. Our results suggest that the poor prognosis previously associated with AML blasts expressing the CD34 antigen may in part be related to high expression of bcl-2. Also the ability to measure bcl-2 in AML blasts quantitatively by flow cytometry and to categorize patients into discrete groups may be of value as a prognostic indicator in AML.

Acute Disease↗
PubMed1995

Functional hyposplenism following allogeneic bone marrow transplantation.

AIMS: To investigate the incidence of functional hyposplenism in a group of patients who had undergone allogeneic bone marrow transplantation (BMT). METHODS: Splenic function was assessed by counting the number of gluteraldehyde fixed red blood cells containing pits or indentations as examined by interference phase microscopy. Normal values are < 2% whereas splenectomy patients have values of 25 to 40%. RESULTS: Twenty eight BMT recipients (17 men, 11 women) were studied at varying periods post-transplant and the results compared with 20 healthy volunteers and 10 patients who had undergone splenectomy or had splenic atrophy because of haematological conditions. Of the 28 BMT recipients, one had undergone a prior splenectomy; of the remaining 27 patients, four (15%) had evidence of functional hyposplenism with between 5.0 and 34.0% pitted cells. Of these four patients, one had active extensive chronic graft versus host disease (GvHD) which has been previously reported to be associated with functional hyposplenism following transplantation. Only one of the four patients had peripheral blood red cell changes typical of hyposplenism. CONCLUSION: These results confirm that extensive chronic GvHD is associated with hyposplenism. Intermediate degrees of functional hyposplenism may also occur following BMT in the absence of chronic GvHD and in the absence of haematological features of hyposplenism on routine blood films. This may be of significance in mediating the susceptibility to infection with encapsulating bacteria seen following allogeneic BMT.

Adolescent↗
PubMed1995

Biological features of leukaemic cells associated with autonomous growth and reduced survival in acute myeloblastic leukaemia.

The blast cells from up to 70% of patients with acute myeloblastic leukaemia exhibit a variable degree of autonomous growth in vitro, which is related to the production of autocrine growth factors. It has recently been established that patients with autonomous blast cell growth have both a lower remission rate and a higher relapse rate, compared to otherwise comparable patients whose blasts exhibit non-autonomous in vitro growth. In a group of 50 patients the actuarial disease-free survival for the autonomous growth group was 11% at 5 years compared to greater than 50% for the non-autonomous growth group. This data suggests that AML blasts with autocrine growth characteristics may be resistant to cytotoxic drug therapy. Here we present further data demonstrating that AML blasts with autonomous growth are relatively resistant to the induction of programmed cell death (apoptosis) and that this is related to the autocrine production of GM-CSF. Also AML blasts with autonomous growths have aberrant expression of genes associated with resistance to apoptosis induced by cytotoxic drugs. These include high expression of the bcl-2 oncoprotein and abnormalities of expression of the p53 tumour suppressor gene. Furthermore bcl-2 expression was found to be unregulated by both exogenous and autocrine GM-CSF suggesting that the documented negative prognostic effect of autonomous growth on treatment outcome in AML, is in part due to the regulatory effect of autocrine GM-CSF on bcl-2 expression, thus protecting cells from apoptosis induced by cytotoxic drug therapy.

Cell Division↗
PubMed1995

Abnormalities of retinoblastoma gene expression in hematological malignancies.

The human retinoblastoma gene product which is involved in cell cycle control and also acts as a transcriptional repressor of genes involved in growth control, is constitutively expressed as a phosphoprotein in normal hemopoietic cells. Abnormalities of the retinoblastoma gene expression leading to loss of protein expression either due to structural changes, mutations or transcriptional abnormalities have been found in a variety of hematological malignancies. There is evidence that loss of Rb protein expression is particularly associated with tumour progression and an adverse response to therapy which may be linked to the biological effect of Rb protein loss on the growth characteristics of tumour cells.

Chromosome Aberrations↗
PubMed1995

Visceral varicella zoster infection after bone marrow transplantation without skin involvement and the use of PCR for diagnosis.

A 41-year-old patient with acute myeloid leukemia was transplanted from an HLA-identical but ABO-incompatible sibling. The post-transplant course was complicated by pure erythrocyte aplasia and mild chronic graft-versus-host disease. Eleven months after transplant while on steroid therapy she developed abdominal pain rapidly followed by fatal fulminant hepatic failure. Varicella zoster virus (VZV) was detected using the polymerase chain reaction from blood and liver obtained at necropsy even though no skin manifestations of VZV were present. This case confirms previous reports of visceral VZV infection in the absence of skin lesions thus emphasising the importance of suspecting the presence of VZV in this clinical setting and outlines the possible value of PCR in the rapid diagnosis of infection.

Adult↗
PubMed1995

Inhibition of bcl-2 with antisense oligonucleotides induces apoptosis and increases the sensitivity of AML blasts to Ara-C.

We have previously shown that blasts from acute myeloid leukaemia (AML) patients which grow autonomously in culture have high bcl-2 expression which in turn has been linked to a poor clinical response to chemotherapy. The bcl-2 protein promotes cell survival by preventing the onset of apoptosis or programmed cell death following growth-factor deprivation. Bcl-2 has also been shown to be responsible for chemo-resistance in human leukaemic cell lines. Here we have investigated the role of bcl-2 expression in mediating resistance to apoptosis induced by cytosine arabinoside in vitro. The blasts from 17 AML patients exhibiting autonomous growth in a blast cell colony assay and expressing high levels of bcl-2 protein were studied. Incubation of the blasts with antisense oligonucleotides directed against bcl-2 mRNA resulted in a significant decrease in expression of the bcl-2 protein in seven of the 17 samples. In these seven cases the decreased expression of bcl-2 was accompanied by increased apoptosis and the susceptibility of the blasts to apoptosis induced by Ara-C was increased in the presence of bcl-2 antisense. As a high level of bcl-2 defines a group of AML patients who exhibit a poor response to chemotherapy, the demonstration that chemosensitivity of a significant proportion of these patients can be increased by bcl-2 antisense suggests this approach may have clinical potential.

Apoptosis↗
PubMed1995

Engraftment characteristics of peripheral blood stem cells mobilised with cyclophosphamide and the delayed addition of G-CSF.

The optimal protocol for the mobilisation of PBSC remains unknown. We present data on 42 patients mobilised with cyclophosphamide (3 or 4 g/m2) and the delayed addition of a standard 300 micrograms dose of G-CSF (Filgrastim) from day +5. The patients had received a median of 2 previous chemotherapy regimes, 38% had received prior radiotherapy and 38/42 had active disease at the time of mobilisation. The protocol was well tolerated and 38 patients proceeded to transplantation. The median number of CD34+ cells reinfused was 4.3 x 10(6)/kg (range 0.5-30) and CFU-GM 15.8 x 10(4)/kg (range 0-148). The total number of CD34+ cells harvested correlated with the total number of CFU-GM available for reinfusion (P = 0.008). Overall engraftment occurred within median days to neutrophils > 0.5 x 10(9)f/l or platelets > 20 x 10(9)/l of 14 and 13 days, respectively. Patients receiving more than 2.5 x 10(6)/kg CD34+ cells had even more rapid haemopoietic reconstitution with significant reductions in hospital stay and transfusion requirements. Those below this threshold had significantly delayed platelet engraftment. The mobilising dose of cyclophosphamide did not influence the achievement of the threshold CD34+ cell yield for optimal engraftment. The delayed addition of a standard 300 micrograms G-CSF dose after priming chemotherapy resulted in the use of a median 9 days hence 9 vials of G-CSF. This protocol presents the potential for cost saving without compromising the quality or success of PBSC mobilisation.

Adult↗
PubMed1994

Wild-type p53 is required for apoptosis induced by growth factor deprivation in factor-dependent leukaemic cells.

The p53 gene is a growth control gene, abnormalities of which have been implicated in a variety of cancers. Recently wild-type p53 has been shown to exist in two interchangeable conformational variants, which can be distinguished by specific p53 monoclonal antibodies. One conformation acts as a suppressor (PAb240-/PAb1620+) and one acts as a promoter (PAb240+/PAb1620-) of cell proliferation; the latter conformation is also that of mutant p53. We have previously shown that acute myeloblastic leukaemia (AML) blasts which proliferate autonomously in vitro express only p53 in the promoter conformation. In contrast, expression of PAb1620 was found only in blasts with non-autocrine growth in vitro and was diminished following stimulation by exogenous growth factors when there was a switch to p53 in the promoter (PAb240+) conformation. As AML blasts with non-autocrine growth undergo apoptosis when deprived of exogenous growth factors, we studied whether this was mediated by wild-type p53. Antisense oligonucleotides to p53 were used to suppress p53 protein expression in blasts with non-autocrine growth and also the factor-dependent human erythroleukaemia cell line TF-1. Following growth factor deprivation for 48 h, 20.6-53.6% of control blasts were apoptotic and demonstrated a typical 'ladder' on DNA electrophoresis characteristic of internucleosomal degradation of DNA. In the presence of p53 antisense, apoptosis was suppressed despite the absence of growth factor, however cell proliferation was not stimulated. We conclude that apoptosis occurring in factor-dependent AML blasts following growth factor deprivation is mediated by wild-type p53 (PAb1620+), and that conformational change of p53 to the PAb240+ conformation occurring either by mutation or by the action of autocrine growth factors would permit leukaemic cell survival by suppressing apoptosis.

Antibodies, Monoclonal↗
PubMed1994

Molecular detection of clonally rearranged cells in peripheral blood progenitor cell harvests from multiple myeloma patients.

Peripheral blood progenitor cells (PBPC) are increasingly used for autologous reconstitution following high-dose chemotherapy in multiple myeloma but it is unclear whether these cells are less likely to be contaminated with malignant cells than bone marrow (BM). We have investigated this using immunoglobulin heavy-chain (IgH) gene fingerprinting, a polymerase chain reaction based technique with a sensitivity of 0.1-0.01% (10(-3)-10(-4)). We have looked for patient-specific IgH rearrangements in leukapheresis samples from eight myeloma patients undergoing PBPC harvest. Seven were in first remission (six partial, one complete) and one in second complete remission. Mobilization of PBPC was accomplished using cyclophosphamide (4 or 7 mg/m2) and rhG- or GM-CSF. Between two and five leukaphereses were performed in each patient. Patient-specific IgH rearrangements were identified in diagnostic BM in all patients and bands of identical size were found in one or more leukaphereses from 6/8 patients. Overall, 14/32 leukaphereses were shown to be contaminated. Two patients who showed contamination of at least one PBPC harvest had BM harvests in which contaminating cells were not detectable, suggesting that PBPC are not necessarily less likely to be contaminated than marrow stem cells. These results indicate that PBPC harvests from the majority of myeloma patients are likely to contain contaminating cells. Further studies are needed to determine whether these cells are clonogenic and whether they contribute to relapse.

DNA Fingerprinting↗
PubMed1994

Intensive treatment of renal failure in patients with myeloma.

We have reviewed our experience in the management of myeloma patients who present with features of severe renal impairment, to examine the role of intensive treatment of the renal failure, and to assess the role of renal biopsy. Between March 1983 and August 1991, 16 patients, who were subsequently diagnosed as having myeloma, presented to the Department of Renal Medicine for investigation of renal failure; nine with symptoms of uraemia and seven with pneumonia, bone pain, emphysema, or ischaemic heart disease. Renal biopsy was performed on 14 patients. Eleven patients had myeloma cast nephropathy, two of whom had concurrent hypertensive nephropathy, two patients had light chain deposition disease, and one patient had interstitial nephritis. Renal function improved in six patients with aggressive rehydration, but three of them subsequently required dialysis. In all 11 patients required dialysis, two short-term and nine long-term. Seven patients were given conventional melphalan and prednisolone and nine patients received VAMP as induction cytotoxic chemotherapy. Five of the VAMP sub-group received interferon alpha 2b as maintenance therapy. The median renal survival was five months (range 0-36 months) and median overall survival was 20 months (range 1-54 months). We conclude that intensive treatment, including dialysis, in myeloma patients with renal failure may result in survival durations approaching those of unselected myeloma patients, and a significant proportion will enjoy a reasonable quality of life.

Adult↗