Search PubMed⌕ Search

Biomedical subjects

F Dreyfus

Publications and source records attributed to F Dreyfus.

At least 55 records · Page 3Linked to original sources
PubMed1998

Analysis of megakaryocyte growth and development factor (thrombopoietin) effects on blast cell and megakaryocyte growth in myelodysplasia.

Thrombocytopenia is a frequent feature of myelodysplastic syndromes (MDS) that could be improved by the use of recombinant human megakaryocyte growth and development factor (rHuMGDF). Using short-term liquid cultures and progenitor assays, we have found that rHuMGDF stimulated DNA synthesis and potentiated leukemic cluster growth of bone marrow mononuclear cells in 10/38 MDS cases (26%). Cytogenetically malignant colonies were detectable in rHuMGDF-stimulated cultures (n=3) by fluorescence in situ hybridization. rHuMGDF was able to stimulate CFU-MK formation in 45% of the samples tested. Finally, rHuMGDF-induced blast cell proliferation correlated with elevated expression of c-MPL, previously identified as a bad prognosis factor in MDS.

Blast Crisis↗
PubMed1998

Quinine improves the results of intensive chemotherapy in myelodysplastic syndromes expressing P glycoprotein: results of a randomized study.

Intensive chemotherapy produces a lower complete remission (CR) rate in the myelodysplastic syndromes (MDS) than in de novo acute myeloid leukaemia (AML), possibly due in part to a higher incidence of P glycoprotein (PGP) expression in MDS blast cells. We designed a randomized trial of intensive chemotherapy with or without quinine, an agent capable of reverting the multidrug resistance (mdr) phenotype, in patients aged < or = 65 years with high-risk MDS. Patients were randomized to receive mitoxantrone 12 mg/m2/d days 2-5 + AraC 1 g/m2/12 h days 1-5, with (Q+) or without (Q-) quinine (30 mg/kg/d). 131 patients were included. PGP expression analysis was successful in 91 patients. In the 42 PGP-positive cases, 13/25 (52%) patients in the Q+ group achieved CR, compared to 3/17 (18%) patients in the Q- group (P = 0.02) and median Kaplan-Meier survival was 13 months in the Q+ group, and 8 months in the Q- group (P = 0.01). No life-threatening toxicity was observed with quinine. In conclusion, the results of this randomized study show that quinine increases the CR rate and survival in PGP-positive MDS cases treated with intensive chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Elevated thrombopoietin serum concentrations in myelodysplasias.

Thrombopoietin (TPO) serum levels were quantified in patients with myelodysplastic syndromes using an ELISA test for TPO. We found that TPO levels were significantly elevated in the whole group of patients as compared with normal healthy donors (521.9 75.3 pg/ml vs 160.1 19.6 pg/ml; P = 0.011). TPO serum levels were inversely correlated with the megakaryocyte mass in both the RA/RARS and RAEB/RAEBt subgroups ( P = 0.012 and P = 0.031, respectively). Two subsets of patients with a possible dysregulation of TPO production were identified.

Journal Article↗
PubMed1998

Thrombopoietin activates human platelets and induces tyrosine phosphorylation of p80/85 cortactin.

The mechanism of human platelet activation by thrombopoietin (TPO) was investigated in vitro. We found that rHuTPO stimulated thromboxane A2 formation and serotonin secretion, despite the absence of shape change and aggregation. Blockade of the arachidonic acid pathway did not inhibit rHuTPO-induced platelet secretion. rHuTPO stimulated the tyrosine phosphorylation of 64, 80/85, 95, 130 and 140 kDa proteins, but phosphoproteins of 100-105 and 125 kDa obtained when platelets aggregated in the presence of thrombin were absent. rHuTPO stimulated and potentiated the thrombin-induced tyrosine phosphorylation of a 80 kDa protein identified as the cortical actin-associated protein, p80/85 cortactin. When platelets were aggregated in the presence of rHuTPO and fibrinogen, cortactin phosphorylation was enhanced as compared to rHuTPO alone. Treatment with RGDS or cytochalasin D respectively reduced or abolished cortactin tyrosine phosphorylation. This confirms the existence of fibrinogen binding-dependent and independent pools of phosphorylated cortactin, both requiring intact actin polymerization. Cytoskeleton-binding proteins may be implicated in in vitro platelet activation by rHuTPO.

Blood Platelets↗
PubMed1998

[Acyclovir-resistance zona in a immunocompromised HIV seronegative patient].

INTRODUCTION: Resistance to antiviral therapy is getting actually more frequent. Immunocompromised host are more concerned with this problem. OBSERVATION: We present a case of disseminated zoster resisting to acyclovir (ACV) therapy, but healing with foscarnet in a man treated with chemotherapy for lymphoma and seronegative for HIV. CI50 of VZV strain was 48 microM for ACV, which was 2.8 times higher than value of the reference OKA strain tested simultaneously, which confirmed the resistance for ACV. DISCUSSION: Immunocompromised patients often present varicella zoster virus (VZV) infection. They usually heal in response to ACV therapy, but some HIV infected patients have already presented with resistant strains of VZV. This case is the first described in a non-HIV infected patient. Foscarnet therapy resulted twice in complete healing because of its direct activity on viral DNA polymerase, so it is efficaceous therapy for patients with thymidine-kinase-deficient ACV-resistant VZV infection.

Acyclovir↗
PubMed1997

Expression of the transcription factor Evi-1 in human erythroleukemia cell lines and in leukemias.

The Evi-1 proto-oncogene is a zinc finger DNA binding protein. Although activation of the Evi-1 gene has been associated with chromosomal rearrangements of the 3q25-q28 region, ectopic expression of Evi-1 could also be observed in acute myelogenous leukemias and myelodysplastic syndromes without cytogenetic abnormalities of the 3q26 locus. In this study, human erythroleukemic cell lines were screened for the expression of Evi-1 mRNA by northern blotting. Evi-1 was expressed in all the erythroid cell lines, whether undifferentiated (K 562, HEL, LAMA 84) or exhibiting spontaneous terminal erythroid differentiation (KU 812, JK-1). Evi-1 mRNA levels were constant or elevated in hemoglobin-synthesizing KU 812 or K 562 cells in response to erythropoietin or hemin treatment, respectively. In human acute myeloblastic leukemias (AML), 11/30 expressed Evi-1 by RT-PCR. Among these cases, 4/6 erythroleukemias without abnormalities of the 3q25-q28 region were found positive. The presence of acidophilic erythroblasts (15-47% of bone marrow cells) accounted for the existence of a terminal erythroid differentiation in all Evi-1-positive AML M6, whereas one negative case was poorly differentiated and referred to as AML M6 variant. These results suggest that Evi-1 mRNA expression can coexist with erythroid differentiation.

Adult↗
PubMed1997

Early allogeneic transplantation favorably influences the outcome of adult patients suffering from acute myeloid leukemia. Société Française de Greffe de Moelle (SFGM).

Allogeneic BMT for patients with acute myeloid leukemia (AML) is presently a reference therapy. The indications for this therapy mainly rely upon prognostic factors, and their importance is constantly reassessed. To examine the impact of time from diagnosis to transplant on survival and leukemia-free survival (LFS), we analyzed 109 patients from the database of the SFGM comprising patients who had all received an HLA-identical allogeneic BMT for a diagnosis of AML in first complete remission (CR1) between January 1987 and December 1992. All patients were conditioned with cyclophosphamide (CY) and total body irradiation (TBI) (CYTBI), and methotrexate (MTX) + cyclosporin A (CsA) were used as graft-versus-host disease (GVHD) prophylaxis. Patient characteristics were: age = 33 +/- 9, M/F = 64/45, white blood cell count (WBC) at diagnosis = 27 +/- 42 x 10(9)/l, FAB distribution: M1 and M2 = 55; M3 = 15, M4 and M5 = 33, M0, M6 and M7 = 6. Karyotyping was carried out for 64 patients: 32 had a normal karyotype, 16 had good prognosis abnormalities (t(8;21), t(15;17), inv 16) and 16 patients had other abnormalities. Eleven patients needed two courses of induction to achieve CR. Time between diagnosis and BMT was 120 (64-287) days. Forty-nine patients developed grade > or = 2 acute GVHD (actuarial probability = 46%). With a median follow-up of 50 months (27-100), the 5-year probabilities for transplant-related mortality (TRM), relapse, overall survival and LFS are respectively 25%, 26%, 59% and 55%. A multivariate analysis showed that survival is adversely influenced by three independent factors: time to transplant (> 120 days vs < or = 120 days), acute GVHD (grade 2-4 vs grade 0-1) and age (> 33 vs < or = 33). LFS is only influenced by the first two of these factors. The favorable impact of a shorter time from diagnosis to transplant should lead to performing the transplant as early as possible. Practically speaking, this means that when such therapy is chosen for a patient with CR1 AML, the search for an allogeneic donor should begin immediately and transplant be performed as soon as possible.

Acute Disease↗
PubMed1997

Fas/Apo-1 (CD95) expression and apoptosis in patients with myelodysplastic syndromes.

Apoptosis of hematopoietic progenitor cells is increased in myelodysplastic syndromes (MDS). We have studied Fas (CD95/Apo-1) antigen expression in 27 MDS patients (RARS 4, RA 3, RAEB 13; RAEB-t 3, CMML 4) and three AML secondary to MDS. We found that the Fas antigen was not expressed on normal bone marrow (BM) CD34+, CD14+, or glycophorin+ cells, and only slightly on CD33+ cells. Patients with MDS had upregulation of Fas expression on total bone marrow nuclear cells (BMMC) (t-test, P = 0.04), CD34+ (P = 0.013), CD33+ (P = 0.04), and glycophorin+ (P = 0.032) BM cells compared to controls. Fas expression did not correlate to the FAB subtype, the Bournemouth score, or to peripheral cytopenias. However, Fas expression intensity on CD34+ cells negatively correlated to the BM blasts number (Spearman, P = 0.01) suggesting that leukemic blasts cells lose Fas antigen expression with progression of myelodysplasia. Using both proliferation assays in liquid cultures and clonogenic progenitor assays in the presence of an agonist anti-Fas MoAb (CH11), we showed that the Fas protein was functional in some patients. Dose-dependent inhibition of DNA synthesis was observed in three out of seven patients studied. CFU-GM and BFU-E colonies suppression in some patients suggested that Fas can induce apoptosis in myeloid and erythroid BM progenitors of MDS patients. The TUNEL technique on BM smears gave a mean of 12.6% +/- 2.5 of bone marrow apoptotic cells in five controls. Patients with MDS had increased bone marrow apoptosis (mean 39% +/- 5.7, t-test, P = 0.012). Four out of 15 (26%) patients studied with a sensitive radiolabeled DNA ladder technique had typical DNA ladders indicative of advanced stages of apoptosis. Massive BM suicide was observed in patients with RA (2/2) and RAEB (8/11), whereas apoptosis rates were normal or low in patients with RAEB-t (3/3) or secondary AMLs (3/3). Moreover, high rates of apoptosis correlated to low Bournemouth score (Spearman, P = 0.01). No statistical correlation could be found between Fas expression and apoptosis rates. Our results confirm the importance of programmed cell death in MDS. The Fas antigen is clearly upregulated on BM cells, but its role in the pathophysiology of apoptosis in myelodysplasia is still unclear, indicating that many factors positively or negatively interfere with the Fas-mediated pathway of apoptosis in vivo and in vitro.

Adult↗
PubMed1997

Age-adapted induction treatment of acute lymphoblastic leukemia in the elderly and assessment of maintenance with interferon combined with chemotherapy. A multicentric prospective study in forty patients. French Group for Treatment of Adult Acute Lymphoblastic Leukemia.

Acute lymphoblastic leukemia (ALL) in the elderly is characterized by its poor prognosis. Forty patients with ALL, aged 55 years or older, and with good performance status (ECOG <3) were prospectively treated according to an age-adapted regimen: induction therapy was derived from the LALA87 protocol while the feasibility of treatment with interferon combined with chemotherapy was assessed during maintenance. Compared with younger adults treated according to the LALA87 protocol, elderly patients did not present with more adverse prognostic features, except for a lower incidence of T cell ALL (9 vs 31%, P=0.005). There were even less patients with a high leukocyte count (15 vs 38%, P=0.003), a characteristic associated with adverse prognosis while the incidence of Philadelphia-positive (Ph-positive) ALL was not significantly increased compared to younger adults (31 vs 20%, P=0.2). After completion of induction therapy, with or without salvage treatment, 85% (CI: 70-94%) obtained a complete response (CR) while treatment-related mortality during induction was 7.5% (CI: 2-20%). Median overall survival and disease-free survival were 14.3 months and 14 months, respectively, which, although inferior to results achieved in younger adults, compares favorably with available data in the elderly. Treatment with IFN proved feasible in most patients but had to be discontinued in eight patients because of toxicity. Age-adapted treatment improves the prognosis of ALL in the elderly even if, in most cases, a cure cannot be achieved.

Aged↗
PubMed1997

[Abnormalities of the expression of cytokines and their receptors in myelodysplastic syndromes].

Abnormalities of the expression of cytokines and their receptors seen in myelodysplastic syndromes (MDS) are reviewed. Autocrine and paracrine secretion of growth factors, most notably GM-CSF and IL-6, has been identified as a factor in clone expansion in young pediatric patients with chronic myelomonocytic leukemia. Mutations affecting cFMS, the receptor for M-CSF, have also been demonstrated. The other reported abnormalities have been found in too small a number of cases to explain the cell growth and differentiation disorders seen during the course of MDS. It remains possible, however, that a more detailed study of signal transduction pathways might detect functional abnormalities explaining the contrast between the small number of reported cases with abnormalities at the cytokine and cytokine receptor sites and the cell growth and differentiation disorders that are prominent in MDS.

Chromosome Aberrations↗
PubMed1996

Factors influencing outcome in de novo myelodysplastic syndromes treated by allogeneic bone marrow transplantation: a long-term study of 71 patients Société Française de Greffe de Moelle.

We report on 71 consecutive patients with de novo myelodysplastic syndromes referred to physicians belonging to the Société française de greffe de moelle from 1982 through 1991 and transplanted with marrow from HLA-identical siblings. There were 16 cases of refractory anemia, 27 of refractory anemia with excess of blast cells, and 28 of refractory anemia with excess of blast cells in transformation. Seventeen patients had received cytoreductive chemotherapy before the graft. The disease progressed in 17 patients between diagnosis and grafting. Twenty-three patients are alive with a median follow-up of 6 years, whereas 24 died from relapse and 24 from transplant-related complications. Kaplan-Meier estimates of event-free survival, relapse and transplant-related mortality at 7 years were 32%, 48%, and 39%, respectively. The log-rank test and Cox's model revealed better outcome among young patients, patients in an early stage of the French-American-British (FAB) classification or with a low percentage of marrow blasts before transplantation, patients who did not undergo cytoreductive chemotherapy before transplantation, and patients conditioned with total body irradiation and cyclophosphamide. The high rate of relapse in advanced FAB stages has led us to graft patients earlier in the course of the disease, and we are currently conducting a multicenter, randomized study to determine the value of intensive chemotherapy before grafting in patients with an excess of marrow blasts.

Adult↗
PubMed1996

STAT-related transcription factors are constitutively activated in peripheral blood cells from acute leukemia patients.

A signal transduction pathway activated by many cytokines has recently been elaborated. The JAK kinases and the signal transducers and activators of transcription (STAT) factors have been found to be essential components. In this report, we describe the presence of constitutively activated STAT factors in peripheral blood cells from patients with acute leukemia. We used oligonucleotide probes from the beta-casein and IRF-1 gene promoters and the ISRE probe to detect STAT proteins in nuclear extracts from acute leukemia cells in bandshift assays. Specific DNA protein complex formation was observed with the probes from the beta-casein and IRF-1 gene promoters, but not with the ISRE oligonucleotide probe, when cell extracts from acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) were investigated. We used nonradioactive oligonucleotides as competitors to show the specificity of the complex formation. Specific antibodies directed against the individual STAT proteins were used in supershift experiments. STAT5- and STAT1-related factors were detected in ALL and STAT1-, STAT3-, and STAT5-related proteins were present in nuclear cell extracts from AML. Since the cells were not treated with cytokines before the nuclear proteins were extracted, we conclude that these factors are constitutively activated in vivo. It is likely that the constitutive activation of STAT proteins is a part of the events of leukemogenesis.

Acute Disease↗
PubMed1996

Timed sequential chemotherapy for advanced acute myeloid leukemia.

Timed sequential chemotherapy (TSC) combining mitoxantrone on days 1-3, etoposide on days 8-10 and cytarabine on days 1-3 and 8-10, was administered to 240 patients with advanced acute myelogenous leukemia (AML). Sixty one percent of patients, with a 95% confidence interval (CI) ranging from 54 to 67%, achieved complete remission (CR), including 47% (CI: 38-55%) of refractory patients and 78% (CI: 70-86%) of late first relapse patients (p < 0.0001). Thirty percent of patients did not respond to therapy and 9% died from toxicity. Median duration of neutropenia was 32 days and of thrombocytopenia 29 days. Severe non hematologic toxicity included sepsis in 45% of patients and mucositis in 27%. Post-remission therapy varied but included maintenance chemotherapy in most patients, a second course of TSC in 27, autologous stem cell transplantation in 17 and allogeneic transplantation in 20. Median survival of patients who were not transplanted was 7 months with 13% (CI: 7-19%) survival at 5 years. Median disease-free survival (DFS) was 9 months with 13% (CI: 6-20%) DFS at 5 years. Previous refractoriness was the main factor associated with poor prognosis for achieving CR, DFS and survival in a multivariate analysis. There was no difference in DFS between patients receiving the different modalities of intensive post-remission therapy. These results confirm initial reports on TSC and show that some patients with first relapse off therapy can enjoy prolonged DFS using chemotherapy only.

Acute Disease↗
PubMed1996

Molecular detection of t(8;21)/AML1-ETO in AML M1/M2: correlation with cytogenetics, morphology and immunophenotype.

The t(8;21) identifies a subgroup of acute myeloid leukaemia (AML) with a relatively good prognosis which may merit different treatment. It is associated predominantly, but not exclusively, with AML M2, and corresponds to rearrangements involving the AML1 and ETO genes. AML1-ETO positive, t(8;21) negative cases are well recognized but their incidence is unknown. In order to determine optimal prospective AML1-ETO RT-PCR screening strategies, we analysed 64 unselected AML M1 and M2 cases and correlated the results with other biological parameters. Molecular screening increased the overall detection rate from 8% to 14%. AML1-ETO was found in 3% (1/32) of AML M1 and 25% (8/32) of M2, including three patients without a classic (8;21) but with chromosome 8 abnormalities. It was more common in younger patients. Correlation with morphology enabled development of a scoring system which detected all nine AML1-ETO-positive cases with a false positive rate of 7% (4/55). Although certain AML1-ETO-positive cases demonstrated characteristic immunological features (CD19 and CD34 expression, CD33 negativity), each of these markers was insufficiently specific to permit prediction in an individual case. We conclude that initial routine prospective molecular screening for AML1-ETO in all AMLs, combined with standardized morphological and immunological analysis, is desirable in order to produce improved prognostic stratification and to determine whether screening can ultimately be restricted to appropriate subgroups.

Adolescent↗