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Biomedical subjects

C Chabannon

Publications and source records attributed to C Chabannon.

At least 73 records · Page 4Linked to original sources
PubMed1996

Autologous transplantation of blood stem cells mobilized with filgrastim alone in 93 patients with malignancies: the number of CD34+ cells reinfused is the only factor predicting both granulocyte and platelet recovery.

High-dose chemotherapy (HDC) supported by autologous transplantation of blood stem cells (BSC) is used increasingly for patients with poor-risk malignancies. We report our experience with 93 consecutive patients who were mobilized with recombinant human granulocyte colony-stimulating factor (rhG-CSF) alone. They received a fixed dose of G-CSF for 5 or 6 days, and BSC were collected by leukapheresis. Aphereses were evaluated for MNC, CD34+ cells, and CFU-GM counts and cryopreserved. All patients received a conditioning regimen without TBI. Engraftment was assessed as the first of 2 consecutive days on which patients achieved 0.5 and 1 x 10(9)/L neutrophils and an unsupported platelet count of 25 x 10(9)/L. Multivariate analysis was performed to study patients and graft characteristics that could influence reconstitution. The G-CSF priming regimen was well tolerated and allowed collection of BSC for all patients, 66% of them achieving >3 x 10(6)/kg CD34+ cells, and 86% achieving >10 x 10(4) CFU-GM/kg. The numbers of collected CD34 and CFU-GM cells were highly correlated. The number of courses of chemotherapy prior to collection, a diagnosis of breast cancer, the use of rhG-CSF posttransplant, and the numbers of CFU-GM and CD34+ cells reinfused were correlated with hematologic recovery. In a multivariate analysis, however, the number of CD34+ cells was the only factor independently influencing both granulocyte and platelet recovery. Patients who received at least 3 x 10(6)/kg CD34+ cells achieved granulocyte reconstitution on day 11 after reinfusion (range 8-15) and an unsupported platelet count of 25 x 10(9)/l on day 14 (range 12-180), significantly earlier than patients who received fewer cells (p < 0.001). In addition, G-CSF administration postreinfusion independently enhanced granulocyte reconstitution but not platelet recovery. In conclusion, CD34+ cell number appears to be the only factor predicting both granulocyte and platelet reconstitution. Based on this study, the collection of a minimal number of 3 x 10(6)/kg CD34+ cells appears desirable.

Adolescent↗
PubMed1996

Photophysical and redox properties of a series of phthalocyanines: relation with their photodynamic activities on TF-1 and Daudi leukemic cells.

The photodynamic therapy (PDT) efficiency of five phthalocyanines, chloroaluminum phthalocyanine (AlPc), dichlorosilicon phthalocyanine (SiPc), bis(tri-n-hexylsiloxy)silicon phthalocyanine (PcHEX), bis(triphenylsiloxy)silicon phthalocyanine (PcPHE) and nickel phthalocyanine (NiPc), was assessed on two leukemic cell lines TF-1 and erythroleukemic and B lymphoblastic cell lines, Daudi, respectively. AlPc showed the best photocytotoxicity leading to 0.008 surviving fraction at 2 x 10(-9) M for TF-1 and 4 x 10(-9) M for Daudi. A1 5 x 10(-7) M, SiPc and PcHEX induced a significant photokilling, whereas NiPc and PcPHE were inactive. Laser flash photolysis and photoredox properties of the phthalocyanines were investigated to try to relate these parameters with the biological effects. AlPc showed the longest triplet life-time: 484 microseconds in dimethyl sulfoxide/H2O. This value was increased up to 820 microseconds when AlPc was complexed with human serum albumin used as a membrane model. Such an enhancement was not observed with the silicon phthalocyanines. Upon irradiation, all the phthalocyanines generated singlet oxygen with 0.29-0.37 quantum yield values. The reduction potentials of the excited states obtained from measurement in the ground state and energy of the excited triplets show that AlPc is the best electron acceptor. The in vitro photocytotoxicity observed and the measured parameters are in agreement with a key role of electron transfer in PDT assays involving these phthalocyanines.

Animals↗
PubMed1996

Human FLT3/FLK2 receptor tyrosine kinase is expressed at the surface of normal and malignant hematopoietic cells.

FLT3/FLK2 is a receptor tyrosine kinase (RTK) which is thought to play an important role in early stages of hematopoiesis. Monoclonal antibodies (mAbs) against the extracellular domain of human FLT3 were generated to study the cell surface expression of this class III RTK on normal bone marrow cells and on leukemic blasts from patients with acute leukemias. Functional analysis of five mAbs (SF1 series) revealed that all of them can mimic to variable extents the activity of the FLT3 ligand (FL) upon receptor activation and modulation, while only one mAb weakly inhibited ligand binding. Using flow cytometry, we detected surface expression of FLT3 on cell lines of the myeloid (4/8) and B lymphoid (7/10) lineages. On normal human bone marrow cells, the expression of FLT3 is restricted, in agreement with a presumed function of this receptor at the level of the stem cells and early committed progenitors. Expression of FLT3 was found on a fraction of CD34-positive and CD34-negative cells. Three-color analysis further revealed that most of the CD34 FLT3+ cells coexpress CD117 (KIT) at a high level. Finally, FLT3 is expressed on leukemic blasts of 18/22 acute myeloid leukemias (AML) and 3/5 acute lymphoid leukemias (ALL) of the B lineage, providing a possible application in diagnosis and therapy of these diseases.

Antibodies, Monoclonal↗
PubMed1996

[Comparative study of the costs for two hematopoietic cell specimen collections: cytapheresis and bone marrow collection].

The aim of this study, carried out at the Institut Paoli-Calmettes (Marseille-France), was to compare, in terms of monetary and non monetary costs, alternate procedures for hematopoietic stem cells collection i.e. peripheral blood stem cells collection (PBSCC) and bone marrow collection (BMC) used in cancer therapies. Monetary costs have been evaluated by calculating the direct costs of the two types of procedures and non monetary costs by comparing anxiety, discomfort and pain of cancer patients submitted to PBSCC or BMC. Patients, randomized (7/1993-2/1994), in view of autologous transplantation, to receive the first procedure or the second one received three self-administered questionnaires to complete before, during and after the procedure. Pain was assessed using visual analogical scale and McGill Pain questionnaire. Anxiety was evaluated by means of State-Trait Anxiety Inventory. Results showed that, under some conditions, presently realized in the current practice, direct costs of PBSCC (10,140 to 13,780 FF) were lower than BMC ones (16,509 FF) and that anxiety and pain experienced by patients submitted to PBSCC, with or without femoral catheter, were significantly less severe than in other group patients (State anxiety, before procedure : p < 0.01 ; pain related to the procedure assessed on VAS : p < 0.001 and total McGill score : p < 0.00001). These findings justify the substitution of bone marrow transplantation by peripheral blood stem cells transplantation, provided there is a demonstration of similar medical efficacy for cancer therapy.

Adult↗
PubMed1996

Administration of G-CSF can be delayed after transplantation of autologous G-CSF-primed blood stem cells: a randomized study.

Hematopoietic growth factors like G-CSF or GM-CSF have been shown to shorten the period of severe neutropenia after HD chemotherapy and autologous BMT, and are now widely used to mobilize hemopoietic stem cells into peripheral blood. In order to evaluate the possibility of delaying G-CSF administration after transplantation of G-CSF mobilized blood stem cells (BSC), we randomized 35 cancer patients to receive CSF at day 1 (group 1, n = 19) or at day 6 (group 2, n = 16) after transplantation and here we present their hematological reconstitution. BSC collection was performed by apheresis after G-CSF priming for 5 or 6 days (600 micrograms daily subcutaneously). Hematological recovery is comparable between the two groups: a median of 10 (range 7-16) vs 11 (range 9-18) days to reach an ANC > 0.5 x 10(9)/1 in group 1 (G-CSF day 1 after transplant) vs group 2 (G-CSF day 6 after transplant, P = NS). Median time to reach an unsupported platelet count of 25 x 10(9)/1 was 14 days in the two groups (range 8-110 and 10-40 respectively, P = NS); patients received less G-CSF after transplantation in group 2. No difference appeared in terms of transfusion support, number of days of fever of i.v. antibiotic treatment. Patients' hospital stay was the same in the two groups. Our data suggest that delaying G-CSF administration after infusion of mobilized blood cells is not detrimental to hematological recovery, while it lowers the overall cost of the procedure.

Adolescent↗
PubMed1996

[Contamination of cytapheresis by tumor cells: apropos of 39 breast cancer cases].

The purpose of the present study was the detection of tumor cells in aphereses after mobilization of peripheral blood stem cells (PBSCs) with G-CSF from 39 breast cancer patients. Circulating tumor cells were searched using sensitive immunocytochemical technique (APAAP) with three anticytokeratin monoclonal antibodies. Counting of mononuclear cells and CD34 progenitor cells was also performed. Circulating tumor cells were detected in 35% of the patients. Cytokeratin-positive cells were detected in 45% of the patients of the metastatic group compared with 20% of the non metastatic one. Aphereses contamination was not correlated with lymph node involvement. Numbers of mononuclear cells and CD34 cells were not significantly different in positive and negative PBSCs collections. In our study, presence of tumor cells was associated with advanced clinical stage and could not be related to a higher CD34 cells mobilization by G-CSF.

Adult↗
PubMed1996

A pilot study of busulfan and melphalan as preparatory regimen prior to allogeneic bone marrow transplantation in refractory or relapsed hematological malignancies.

In this pilot study; we assessed the immunosuppressive and the antileukemic potential of a combination of busulfan and melphalan prior to allogeneic BMT in 25 adult patients with refractory or relapsed hematological malignancies. Twelve patients were transplanted for acute myeloid leukemia (relapse: five patients; primary refractory: four patients; second remission: two patients), two patients for primary refractory acute lymphoblastic leukemia, nine patients for chronic myelogenous leukemia (accelerated phase: six patients; blastic phase: three patients) and two patients for primary refractory lymphoma. All received an unmanipulated marrow from HLA-identical siblings. All patients but one engrafted (median time to ANC > or = 0.5 x 10(9)/l = 17 days, to platelets > or = 50 x 10(9)/l = 29 days). Full chimerism was documented in the seven evaluable patients. The probability for developing acute GVHD was 58%. Complete remission was obtained in 17/18 measurable patients. With a 42 month median follow-up, eight patients are alive in unmaintained remission. The 4-year probabilities for relapse, survival, and DFS are respectively: 42%, 35%, and 31%. These results show that the combination of busulfan and melphalan ensures an effective immunosuppression allowing long-term engraftment. This regimen can provide long-term disease-free survival in patients with high-risk disease and thus represents an interesting alternative to the CY and/or TBI-containing regimens.

Adult↗
PubMed1995

Patient condition affects the collection of peripheral blood progenitors after priming with recombinant granulocyte colony-stimulating factor.

A total of 258 aphereses were performed in 79 patients with nonmyeloid malignancies after mobilization of peripheral blood stem cells (PBSC) with recombinant human granulocyte colony-stimulating factor (rhG-CSF). Apheresis products were examined for viable mononuclear cell (VMC), CD34+ cell, and clonogenic cell contents. The number of progenitors in aphereses differs in subgroups of patients with different diagnoses. However, the number of CD34+ or clonogenic cells is dependent on age and amount of chemotherapy delivered to patients before collection rather than on the nature of the disease itself. In addition, the actual dose of rhG-CSF used to mobilize PBSC and the number of VMC in aphereses influenced the clonogenicity of CD34+ cells, although the daily dose of rhG-CSF seems to play little role on the number of clonogenic cells in each individual apheresis product. CD34+ cell and CFU-C (or CFU-GM) numbers are related parameters, and the relation can be described as linear. However, the linear relation varies in different patient groups, and most of the linearity is induced by the highest sets of values. We conclude that mobilization with low doses of rhG-CSF alone is feasible and that the probability of collecting a high number of peripheral blood progenitors is increased in young patients undergoing apheresis early in the course of the disease. Although the relationship between CD34+ cells and CFUs can be described as linear in well-defined situations, its relevance may be limited because it is not a universal finding.

Adolescent↗
PubMed1995

Ex vivo expansion of human peripheral blood progenitors.

Culture of human hematopoietic progenitors on a large scale could lead to several clinical applications within the near future, including the production of differentiated and functional cells, the increase in the number of early progenitors, especially stem cells, with such use as gene transfer, or the improvement of grafts used to limit the hematological toxicity associated with high-dose chemotherapy. In this case, one can still distinguish different objectives: improvement of grafts that contain low numbers of progenitors because of prior chemotherapies or because of marrow involvement for example, and qualitative changes in the graft content that would allow to envision the disappearance, or the further reduction, in the duration of absolute neutropenia that follows delivery of high dose chemotherapy ("nadir rescue"), despite substitution of mobilized blood cells to marrow cells and the in vivo use of hematopoietic growth factors. Additional advantages may be related to tumor purging in autologous expanded cells, and to the change in the ratio between hematopoietic progenitors and immunocompetent cells in allogeneic expanded populations. Therefore it appears that in vitro expansion currently raises two types of questions: the first ones are related to the definition of clinical or biological endpoints to be achieved, the second ones are related to "bioengineering", and deal with the efficiency and safety of progenitor cell cultures to be used for clinical applications. We here present preliminary results preparing future pilot clinical studies with ex vivo cultured human hematopoietic cells.

Antigens, CD↗
PubMed1994

A review of 76 patients with myelodysplastic syndromes treated with danazol.

BACKGROUND: Treatment of myelodysplastic syndromes (MDSs) remains unsatisfactory. A limited number of reports provide contradictory information on whether danazol, a synthetic androgen, may be useful in patients with MDS. METHODS: Between 1984 and 1992, 76 patients were treated with danazol (Danatrol, Winthrop) in an open nonrandomized study. Clinical status, blood counts, differential marrow cell counts, transfusion requirements, and liver enzymes were monitored at 3-month intervals during and 6 months after discontinuation of therapy. The authors present the retrospective analysis of this cohort of patients. RESULTS: This study shows a limited usefulness of danazol in patients with MDS. Blood counts were not significantly changed during danazol administration; neither were transfusion requirements. Overall survival and the rate of leukemic transformation were not affected when compared with 50 untreated patients or with data available in the literature. An increase in platelet numbers in four patients and in hemoglobin level in one patient was observed; these patients were unremarkable and were not transfused before initial danazol therapy; therefore, changes in blood counts were of limited clinical significance. The search for subgroups of patients likely to have a favorable response was unsuccessful. Side effects of danazol were limited. In addition, this study provides information on the frequency of antiplatelet antibodies and other autoantibodies in patients with MDS. CONCLUSIONS: This study does not support a positive effect of danazol in patients with MDS during long term follow-up. Anecdotal positive evolution in a few patients cannot be formally ascribed to danazol. These results should be interpreted by comparison with previous publications that report on small numbers of patients with limited follow-up. Based on these data, the authors cannot recommend the systematic use of danazol in MDS.

Adult↗
PubMed1994

A case of polycythemia vera occurring in a patient with acute non-lymphoblastic leukemia (ANLL) in long-term first complete remission.

Polycythemia vera (PV) is a chronic myeloproliferative syndrome which in a minority of patients evolves into acute leukemia. The association with other hematopoietic malignancies has also been reported. The relationship between PV, leukemia, and treatment used for PV remains unclear. We here report the unusual observation of a young patient who developed the complete clinical and biological picture of PV, 6 years after being successfully treated with conventional chemotherapy for acute non-lymphoblastic leukemia (ANLL).

Adult↗
PubMed1992

Expression of CD7 on normal human myeloid progenitors.

Existence of biphenotypic leukemias co-expressing CD7 and CD34 has prompted the question of whether a similar population of cells is present in normal human bone marrow. As CD7 is considered to be a T cell-restricted Ag, the co-expression of CD7 with the "human stem cell Ag" CD34 may identify a bipotent stage within hemopoietic differentiation. Cells with this phenotype have previously been isolated from human thymus. In this report we provide evidence that human marrow mononuclear cells also contain a minor subpopulation of cells co-expressing CD7 and CD34. The CD7+/CD34+ cells were found to contain committed myeloid progenitors assayed both as CFU in semi-solid media and by their ability to produce granulocytes in long term marrow cultures. Expression of CD7 on myeloid committed progenitors was further confirmed in a C-mediated cytotoxic assay. We conclude that CD7 expression is not restricted to T cells but is also expressed during early stages of myeloid differentiation.

Antigens, CD↗
PubMed1991

Role of splenectomy in incidence and severity of acute graft-versus-host disease: a multicenter study of 157 patients.

Allogeneic bone marrow transplantation is a therapeutic option for many hematological malignancies. Graft-versus-host disease (GVHD) remains one of the major complications and has a high mortality rate. The pathophysiological mechanisms involved are poorly understood and GVHD prevention regimens still give disappointing results. This study concerned 157 patients with diverse diagnoses from Bordeaux, Grenoble and Marseille who had undergone an HLA-matched transplantation without T cell depletion. Thirty-one patients (20%) had been splenectomized before transplantation. The role of splenectomy in the incidence and severity of acute GVHD was investigated using a univariate and multivariate analysis of 11 risk factors including splenectomy. Univariate analysis found three significant risk factors linked with GVHD incidence: splenectomy, age of recipient and GVHD prevention by monotherapy versus a combination of methotrexate plus cyclosporin. Multivariate analysis retained only the effects of age and GVHD prevention on GVHD incidence and showed that splenectomy was the most important factor in GVHD severity. One explanation for the role of splenectomy could be the spleen's possible function as a filter of activated T lymphocytes from the transplant. We therefore concluded that it would be preferable to abstain from splenectomizing patients before transplantation although splenectomy is still advisable in certain malignancies after transplantation.

Acute Disease↗