Multidrug resistance and myelomonocytic leukaemia in gaucher's disease.
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Bone Marrow Examination↗
Biomedical subjects
A B Mehta
Publications and source records attributed to A B Mehta.
Pancytopenia responding to treatment of hyperthyroidism: a clinical case and review of the literature.
A 46-year-old-man received high dose chemotherapy and an autologous stem-cell transplant for multiple plasmacytoma. He had a prolonged period of pancytopenia post-transplantation, which was thought to be due to a suboptimal dose of transplanted stem cells in combination with the effects of interferon therapy and an altered bone marrow microenvironment. Twenty-eight months after the transplant he was found to be hyperthyroid. Anti-thyroid therapy has led to a sustained improvement in his pancytopenia.
Antineoplastic Agents, Alkylating↗
Caspase 8 activation independent of Fas (CD95/APO-1) signaling may mediate killing of B-chronic lymphocytic leukemia cells by cytotoxic drugs or gamma radiation.
Ligation of the cell-surface Fas molecule by its ligand (Fas-L) or agonistic anti-Fas monoclonal antibodies results in the cleavage and activation of the cysteine protease procaspase 8 followed by the activation of procaspase 3 and by apoptosis. In some leukemia cell lines, cytotoxic drugs induce expression of Fas-L, which may contribute to cell killing through the ligation of Fas. The involvement of Fas, Fas-L, and caspase 8 was studied in the killing of B-cell chronic lymphocytic leukemia (B-CLL) cells by chlorambucil, fludarabine, or gamma radiation. Spontaneous apoptosis was observed at 24-hour incubation, with additional apoptosis induced by each of the cytotoxic treatments. Although Fas mRNA expression was elevated after exposure to chlorambucil, fludarabine, or gamma radiation, Fas protein levels only increased after irradiation. Therefore, Fas expression may be regulated by multiple mechanisms that allow the translation of Fas mRNA only in response to restricted cytotoxic stimuli. None of the cytotoxic stimuli studied here induced Fas-L expression. An agonistic anti-Fas monoclonal antibody (CH-11) did not significantly augment apoptosis induction by any of the death stimuli. A Fas-blocking antibody (ZB4) did not inhibit spontaneous, chlorambucil-, fludarabine-, or radiation-induced apoptosis. However, procaspase 8 processing was induced by all cytotoxic stimuli. These data suggest that the Fas/Fas-L signaling system does not play a major role in the induction of apoptosis in B-CLL cells treated with cytotoxic drugs or radiation. However, Fas-independent activation of caspase 8 may play a crucial role in the regulation of apoptosis in these cells.
Antibodies, Monoclonal↗
Multiple myeloma and human immunodeficiency virus-1 (HIV-1) infection.
Multiple myeloma (MM) in three human immunodeficiency virus (HIV)-infected patients is reported. HIV infection predisposes to the development of high-grade B-cell lymphomas, but few cases of plasma cell tumours in association with HIV have been reported. The coincidence of HIV infection and neoplasia highlights the distinct roles of immunodeficiency and infection with herpesviridae, including HIV itself, in the pathogenesis of HIV-related tumours. In addition, a number of cytokines (e.g., interleukin-6 [IL-6]) and angiogenic factors (e.g., vascular endothelial growth factor [VEGF] and basic fibroblastic growth factor [bFGF]) may play a role in the initiation, maintenance, and progression of multiple myeloma (MM). Infection was the first clinical consideration to the cause of the illness in two of our HIV-seropositive patients. The diagnosis of MM may be difficult in patients with advanced HIV infection as they often have renal failure, bone marrow plasmacytosis, repeated infections, and polyclonal hypergammaglobulinaemia, due to HIV infection itself, opportunistic pathogens, and/or medication.
Adult↗
Heterogeneity of VH-JH gene rearrangement patterns: an insight into the biology of B cell precursor ALL.
Oligoclonal B cell proliferation, as defined by the presence of more than one leukemic clone, has been detected in approximately 20% to 30% of patients with acute lymphoblastic leukemia (ALL) using PCR or Southern blotting. An accurate assessment of these populations is required to avoid false negative measurements of minimal residual disease (MRD) in follow-up bone marrow (BM) samples of ALL patients. In this study, we analysed 29 ALL patients with two or more immunoglobulin heavy (IGH) chain gene rearrangements in the presentation samples using IGH fingerprinting PCR and sequence analysis. Thirty-nine (51%) of 76 sequences (from 15 patients), shared no VNDNJ homology (ie different CDR3 regions). In the remaining 14 patients, at least two related VH sequences were identified in each patient (identical DNJ sequences). Numerical abnormalities of chromosome 14 was detected in 10 patients. Eight patients were analysed at presentation and relapse. In four of them, expansion of a minor presentation-clone was detected at relapse while the major presentation clone disappeared, confirming 'subclonal evolution'. Finally, in our cohort of patients, the presence of related or unrelated IGH clones did not influence overall survival.
Adolescent↗
A multicentre, open, non-comparative phase II study of a combination of fludarabine phosphate, cytarabine and granulocyte colony-stimulating factor in relapsed and refractory acute myeloid leukaemia and de novo refractory anaemia with excess of blasts in transformation.
The primary objective of this study was to determine the complete remission (CR) rate achieved with the FLAG (fludarabine phosphate, cytarabine and granulocyte colony-stimulating factor) regimen in patients with relapsed or refractory acute myeloid leukaemia (AML) or de novo refractory anaemia with excess of blasts in transformation (RAEB-t). Secondary objectives were to evaluate survival and toxicity. Induction treatment consisted of between one and two courses of FLAG. Patients achieving CR received between one and two courses of consolidation treatment. Eighty-three of the 89 patients entering the study were eligible for assessment. CR rates were: 17 out of 21 (81%) in late relapse AML (Group 1), 13 out of 44 (30%) in early relapse/refractory AML (Group 2), and 10 out of 18 (56%) in de novo RAEB-t (Group 3). Thirty-four of the 40 responders (85%) achieved CR after one induction course. Median survival times were 1.4 years, 3 months and 1.6 years in Groups 1, 2 and 3 respectively. Other than myelosuppression, the FLAG regimen was not generally associated with clinically significant toxicity and was well tolerated by most patients including the elderly. The FLAG regimen offers a very effective alternative treatment for CR induction in poor prognosis adult patients with either relapsed or refractory AML or de novo RAEB-t. FLAG delivers high-dose treatment without increasing overall toxicity, an approach which is of particular value in older patients, who constitute the majority in these diseases. It is therefore an important advance in developing new treatment options for these patients.
Acute Disease↗
The hepatologist in the haematologists' camp.
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Acute Disease↗
Autologous plasma activates Akt/protein kinase B and enhances basal survival and resistance to DNA damage-induced apoptosis in B-chronic lymphocytic leukaemia cells.
We have studied the actions of autologous plasma on both basal and DNA damage-induced apoptosis in B-chronic lymphocytic leukaemia (B-CLL) cells. Apoptosis was quantified using morphological criteria and Western blot analysis for the apoptosis-specific p85 fragment of poly(ADP ribose) polymerase. Cell viability was estimated using the methyl thiazol tetrazolium bromide dye reduction assay. Plasma cultures showed lower rates of basal apoptosis as well as a decreased cytotoxic response to chlorambucil and gamma-radiation compared with cultures in fetal calf serum. Experiments using neutralizing antibodies suggested that the protective actions of plasma could not be accounted for by interleukin 4, the interferons alpha or gamma or stromal cell-derived factor 1, each of which have been shown to protect B-CLL cells from apoptosis in vitro. Plasma addition to B-CLL cells resulted in rapid activation of the Akt protein kinase, a key signalling enzyme that has been implicated in anti-apoptotic signalling. LY294002, an inhibitor of phosphatidylinositol 3'-kinase, blocked Akt activation by plasma. To the best of our knowledge, this is the first report to show that factors present in plasma promote basal survival of B-CLL cells and resistance to cytotoxic drugs via stimulation of the Akt cytoprotective-signalling pathway. Pharmacological blockade of this pathway may have potential in the development of novel therapeutic strategies for B-CLL treatment.
Antineoplastic Agents, Alkylating↗
Thrombopoietin concentration after orthotopic liver transplantation.
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Humans↗
The PML-RAR alpha transcript in long-term follow-up of acute promyelocytic leukemia patients.
BACKGROUND AND OBJECTIVES: Detection of PML-RAR alpha transcripts by RT-PCR is now established as a rapid and sensitive method for diagnosis of acute promyelocytic leukemia (APL). Although the majority of patients in long-term clinical remission are negative by consecutive reverse transcription polymerase chain reaction (RT-PCR) assays, negative tests are still observed in patients who ultimately relapse. Conversion from negative to positive PCR has been observed after consolidation and found to be a much stronger predictor of relapse. This study reports on 47 APL patients to determine the correlation between minimal residual disease (MRD) status and clinical outcome in our cohort of patients. DESIGN AND METHODS: The presence of PML-RAR alpha t transcripts was investigated in 47 APL patients (37 adults and 10 children) using a semi-nested reverse transcriptase-polymerase chain reaction to evaluate the prognostic value of RT-PCR tests. RESULTS: All patients achieved complete clinical remission (CCR) following induction treatment with all-trans retinoic acid (ATRA) and chemotherapy (CHT) or ATRA alone. Patients were followed up between 2 and 117.6 months (median: 37 months). Relapses occurred in 11 patients (9 adults and 2 children) between 11.4 and 19 months after diagnosis (median: 15.1 months) while 36 patients (28 adults and 8 children) remained in CCR. Seventy-five percent of patients carried the PML-RAR alpha long isoform (bcr 1/2) which also predominated among the relapsed cases (9 of 11) but did not associate with any adverse outcome (p= 0.37). For the purpose of this analysis, minimal residual disease tests were clustered into four time-intervals: 0-2 months, 3-5 months, 6-9 months and 10-24 months. INTERPRETATION AND CONCLUSIONS: Children showed persisting disease for longer than adults during the first 2 months of treatment. At 2 months, 10 (50%) of 20 patients who remained in CCR and 4 (80%) of 5 patients who subsequently relapsed were positive. Patients who remained in CCR had repeatedly negative results beyond 5.5 months from diagnosis. A positive MRD test preceded relapse in 3 of 4 tested patients. The ability of a negative test to predict CCR (predictive negative value, PNV) was greater after 6 months (>83%), while the ability of a positive test to predict relapse (predictive positive value, PPV) was most valuable only beyond 10 months (100%). This study (i) highlights the prognostic value of RT-PCR monitoring after treatment of APL patients but only from the end of treatment, (ii) shows an association between conversion to a positive test and relapse and (iii) suggests that PCR assessments should be carried out at 3-month intervals to provide a more accurate prediction of hematologic relapses but only after the end of treatment.
Adolescent↗
Killing of T lymphocytes by synthetic ceramide is by a nonapoptotic mechanism and is abrogated following mitogenic activation.
Ceramide induces apoptosis in leukemia cell lines and has been proposed as a potential therapeutic agent in malignancies refractory to conventional treatment. Here we show that synthetic N-acetyl-d-erythro-sphingosine (C2 ceramide) kills normal human T lymphocytes by a caspase-independent nonapoptotic mechanism. By contrast, T cells were induced to caspase-dependent apoptosis by okadaic acid. Furthermore, C2 ceramide treatment of the Jurkat leukemia cell line induced killing by apoptosis. Activation of T lymphocytes by phytohemagglutinin abrogated killing by C2 ceramide. The data here suggest that ceramide triggers caspase-dependent apoptosis in leukemia cells lines, but activates caspase-independent nonapoptotic killing of resting T lymphocytes which is abrogated following mitogenic activation.
Amino Acid Chloromethyl Ketones↗
Ceramide-induced killing of normal and malignant human lymphocytes is by a non-apoptotic mechanism.
Synthetic ceramides induce apoptotic death of Jurkat and HL60 leukaemia cell lines. By contrast we show here that ceramide induces non-apoptotic killing of malignant cells from patients with B-chronic lymphocytic leukaemia (B-CLL) and of normal B lymphocytes. The protein phosphatase inhibitor okadaic acid readily induces apoptosis of B-CLL cells, indicating that this death pathway is fully functional in these cells. The ability of ceramide to activate the apoptotic protease caspase 3 in HL60 cells but not in B-CLL cells, as well as the lack of correlation of ceramide-mediated killing of different B-CLL isolates with expression of the apoptosis-regulating proteins bcl-2 and bax reinforce the conclusion that ceramide killing of B-CLL cells is by a non-apoptotic mechanism. Fludarabine treatment or gamma-irradiation of B-CLL cells resulted in ceramide elevation and in killing by both apoptotic and non-apoptotic mechanisms, suggesting that a ceramide-triggered non-apoptotic mechanism may play a role in the killing of these cells. Therefore, the results here show that ceramide can induce either apoptotic or non-apoptotic death, depending on the cellular context. The inability of synthetic dihydroceramide to kill B-CLL cells or normal B lymphocytes suggests that non-apoptotic killing by ceramide is via interaction with a specific, but unidentified, cellular target.
Amidohydrolases↗
Serum soluble transferrin receptor in the diagnosis of iron deficiency in chronic liver disease.
Fifty-one consecutive patients with chronic liver disease (CLD) underwent investigations of their iron status (full blood count, serum iron [Fe], total iron binding capacity [TIBC], transferrin saturation [TS], serum ferritin and serum soluble transferrin receptor [sTfR] level). Twenty-six patients were anaemic; 12 patients had iron deficiency, and 10 had iron deficiency anaemia (IDA). The median (range) sTfR in the IDA patients was 16.6 (11.2-24.8) mg/l. compared with 6.6 mg/l (11.2-24.8) in the 16 patients with anaemia due to other causes (P = 0.01). The sensitivity of sTfR for diagnosing iron deficiency in CLD was 91.6% (100% if only anaemic patients are included) and the specificity was 84.6%. Patients with haemolysis and recent blood loss may have falsely elevated sTfR levels. The results suggest that the sTfR is as useful as serum ferritin in identifying a potentially treatable cause of anaemia in CLD.
Adolescent↗
Thrombopoietin concentrations are low in patients with cirrhosis and thrombocytopenia and are restored after orthotopic liver transplantation.
BACKGROUND: Thrombocytopenia in cirrhotic patients may be due to deficient production of thrombopoietin. AIMS: To determine the relation between thrombopoietin and thrombocytopenia in cirrhotic patients before and after orthotopic liver transplantation. METHODS: Thrombopoietin concentrations and platelet counts were measured in 43 cirrhotic patients and 21 normal controls and serially for 14 days after transplantation in 23/43 patients. RESULTS: 27 of the 43 patients had thrombocytopenia (platelet count less than 120 x 10(9)/l; group 1) whereas 16 patients had normal platelet count (group 2). Thrombopoietin concentrations were lower in group 1 than in group 2 (92.5 (20.3-286.3) v 226.6 (30.1-848.3) pg/ml, p=0.003) and normal controls (92.5 (20.3-286.3) v 158.3 (22.5-232.9) pg/ml, p=0.028). Post-transplantation thrombopoietin concentrations increased with a peak at day 5. The rise was significant in patients with low pretransplantation platelet count (89.1 (21.29-247.6) to 545.1 (66.2-2569) pg/ml; n=16, p=0.001) but not in those with normal platelet count (262.8 (30.1-848.3) to 315.1 (114-954.6) pg/ml; n=7, p=0.47). No correlation was found pretransplantation between spleen volume and platelet count (r=-0.11, p=0.6) or thrombopoietin concentrations (r=-0.04, p=0.8). However, pretransplantation thrombopoietin concentrations correlated with platelet count (r=0.47, p=0.0015), whereas an inverse correlation was found between peak thrombopoietin concentrations and nadir platelet count (r=-0.41 p=0. 049) post-transplantation. CONCLUSIONS: Inadequate thrombopoietin production may contribute to cirrhotic thrombocytopenia. Thrombopoietin production is restored after liver transplantation leading to the resolution of thrombocytopenia.
Adult↗
Okadaic acid-induced apoptosis of HL60 leukemia cells is preceded by destabilization of bcl-2 mRNA and downregulation of bcl-2 protein.
We have studied the actions of the protein phosphatase inhibitor okadaic acid (OA) on the expression of bcl-2 in HL60 human leukemia cells. OA induced downregulation of bcl-2 mRNA and protein prior to the induction of apoptosis. Downregulation of bcl-2 mRNA levels did not result from actions of OA on the bcl-2 upstream negative response element. Nuclear run-off analyses confirmed that OA did not affect bcl-2 gene transcription. However, OA caused a rapid increase in the rate of degradation of bcl-2 mRNA. Therefore, OA induces down-regulation of bcl-2 expression via destabilization of its transcript. The constitutive action of an OA-sensitive protein phosphatase may therefore maintain HL60 cell survival by blocking bcl-2 mRNA degradation.
Apoptosis↗
Herbimycin A accelerates the induction of apoptosis following etoposide treatment or gamma-irradiation of bcr/abl-positive leukaemia cells.
Philadelphia chromosome (Ph)-positive leukaemia cells express the chimeric bcr/abl oncoprotein, whose deregulated protein tyrosine kinase (PTK) activity antagonizes the induction of apoptosis by DNA damaging agents. Treatment of Ph-positive K562, TOM 1 and KCL-22 cells with etoposide for 2d induced cytosolic vacuolation, but not nuclear condensation or DNA fragmentation. The bcr/abl kinase-selective inhibitor herbimycin A increased the induction of nuclear apoptosis by etoposide or gamma-radiation. The concentration of herbimycin required to synergize with etoposide was similar to that required to decrease the level of tyrosine phosphorylated proteins or of the protein tyrosine kinase activity of anti-abl immune complexes in K562 cells. The ability of herbimycin A to sensitize K562, TOM 1 or KCL-22 cells to apoptosis induction correlated with its ability to decrease the cellular content of phosphotyrosyl proteins in these Philadelphia-positive lines. Enhancement of nuclear apoptosis by herbimycin was not attributable to downregulation of the bcl-2 or bcl-XL anti-apoptotic proteins. In contrast, herbimycin protected Philadelphia-negative HL60 cells from apoptosis induction by etoposide and did not affect killing of NC37 and CEM cells. The data suggest that the induction of apoptosis is blocked in cells expressing the bcr/abl oncoprotein and that herbimycin A increases induction of programmed cell death following DNA damage. Selective PTK inhibitors may therefore be of value in securing the genetic death of Ph-positive leukaemia cells.
Antibiotics, Antineoplastic↗
Myelodysplastic syndromes associated with 11q23 abnormalities. European 11q23 Workshop participants.
Most hematological neoplasms associated with 11q23 chromosomal rearrangement have been cases of acute lymphoblastic or acute myeloid leukemia. Although cases of myelodysplastic syndrome (MDS) are a minority, these syndromes should also be recognized as part of the spectrum of hematological disorders associated with 11q23 rearrangement. In this series of 550 patients with such rearrangement there were 28 (5.1%) who presented with MDS. A further five patients had a history of MDS but had evolved to AML by the time cytogenetic analysis was first undertaken. There were thus a total of 33 patients (6.0%) with an 11q23 abnormality whose initial presentation was as MDS. Of these 33 patients, a quarter (seven patients) were cases of secondary (therapy-related) MDS. Complex karyotypes and other poor prognosis chromosomal abnormalities such as -7 and 7q- were common and were not confined to secondary cases. The likelihood of presentation as MDS differed between different cytogenetic categories. The 28 patients in whom cytogenetic analysis was performed at presentation as MDS showed a wide age distribution, from 1 to 82 years; there were four children, two of 1 year of age. All FAB types of MDS were represented. Median survival was only 19.1 months. Leukemic transformation occurred in five patients including one case of transformation to a biphenotypic M5a/T-lineage acute leukemia.
Adolescent↗
Secondary acute leukemia and myelodysplastic syndrome with 11q23 abnormalities. EU Concerted Action 11q23 Workshop.
Forty of the 550 patients (7%) entered to the 11q23 Workshop had secondary (s) acute lymphoblastic leukemia (nine cases), s-acute myeloid leukemia (25 cases, predominantly of FAB type M5), s-acute leukemia unspecified (one case) or s-myelodysplastic syndrome (five cases) following treatment for a primary malignancy. Breast cancer (12 cases) and non-Hodgkin's lymphoma (eight cases) were the most frequent primaries. Twenty-three patients had been treated with either an epipodophyllotoxin (seven patients) or an anthracycline (10 cases) or both (four cases) frequently combined with alkylating agents (12 cases) and with radiotherapy (six cases). Two further patients had alkylating agents and two had radiotherapy alone. Time between diagnosis of the primary and secondary malignancy was between 10 months and 22 years (median 24 months). The incidence of secondary malignancies in 11q23 subgroups was: t(11;19)(q23;p13.1) (33%), t(9;11) (8%), t(4;11) (5.5%), t(10;11)(5%), t (6;11) (3%), del11q23(2%) and 10 patients had a rare 'other' abnormality. No associations were seen between type of prior malignancy and 11q23 subgroup, or between prior malignancy and leukemia subtype. Remission, when achieved (32 patients), was short (median 5 months). Two patients survived following a bone marrow transplant for s-leukemia and s-myelodysplastic syndrome.
Acute Disease↗