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T Guillaume

Publications and source records attributed to T Guillaume.

At least 19 recordsLinked to original sources
PubMed2003

[Abnormalities in serum magnesium concentration].

Magnesium (Mg) therapy is often proposed against stress and to correct asthenia. Thus our aim has been to review the role of Mg, the mechanisms of its homeostasis before detailing the clinical presentations and etiologies of hypo- and hypermagnesemia and their exploration. Hypomagnesemia frequently occurs but is clinically rarely recognized without biological serum ionic determinations because causing atypical signs miming those of other ion deficiencies. Hypermagnesemia is uncommon but often occurs in the presence of renal insufficiency especially with excess of Mg administration.

Humans↗
PubMed2000

Pitfalls in the detection of disseminated non-hematological tumor cells.

There is not yet a consensus on the reliability of the methods that should be used for the detection of rare disseminated tumor cells from non-hematological malignancies. In this review, we will discuss the advantage and drawbacks of the classical approach of immunocytochemistry and the molecular detection by reverse transcriptase polymerase chain reaction (RT-PCR). The interpretation of the biological significance of circulating tumor cells and the pitfalls of the detection techniques are the main causes of discrepancy between the conclusions of different tumor-cell detection (TCD) studies.

DNA, Neoplasm↗
PubMed2000

Highly purified CD34+ cells isolated using magnetically activated cell selection provide rapid engraftment following high-dose chemotherapy in breast cancer patients.

The primary objective of this study was to evaluate the safety of infusion of CD34+ cells, selected using a clinical scale magnetically activated cell sorting device, assessed by time to hematological engraftment and incidence of adverse events. Secondary objectives included evaluation of device performance in terms of purity and recovery of the CD34+ cell product. Breast cancer patients suitable for transplantation received cyclophosphamide and filgrastim for mobilisation, followed by three leukaphereses. The products of the first two leukaphereses underwent CD34+ cell selection. The product of the third leukapheresis was cryopreserved unmanipulated. Following high-dose cyclophosphamide, thiotepa and carboplatin, selected CD34+ cells were infused. In 54 patients who received selected cells only, the median time to platelet recovery and neutrophil recovery was 11 days (range 5-51) and 9 days (range 5-51), respectively. There were no adverse events associated with infusion of selected cells. A total of 126 leukapheresis samples was available before and after selection for central CD34+ analysis. The median purity was 96.1% (27.4-99.4) and the median recovery was 52. 3% (15.2-146.3). These data show that cells selected using magnetically activated cell selection provide safe and rapid engraftment after high-dose therapy. Bone Marrow Transplantation (2000) 25, 243-249.

Adolescent↗
PubMed1999

Retrovirus-mediated gene transfer of the human multidrug resistance-associated protein into hematopoietic cells protects mice from chemotherapy-induced leukopenia.

Utilization of chemotherapy for the treatment of tumors is mainly limited by its hematological toxicity. Because of the low-level expression of drug resistance genes, transduction of hematopoietic progenitors with multidrug resistance 1 (MDR1) or multidrug resistance-associated protein (MRP) genes should provide protection from chemotherapeutic agent toxicity. Successful transfer of drug resistance genes into hematopoietic cells may allow the administration of higher doses of chemotherapy and, thus, increase regression of chemosensitive tumors. The interest in the use of MRP as an alternative to MDR1 for bone marrow protection lies in its different modulation. This would allow, in the same patient, the use of MDR1 reversal agents to decrease MDR1 tumor resistance without reversing bone marrow (BM) protection of the MRP-transduced hematopoietic cells, since MRP expression is not reversed by these agents. We have constructed MRP-containing retroviral vectors using the phosphoglycerate kinase promoter and generated ecotropic producer cells. Lethally irradiated mice were engrafted with BM cells transduced by coculture with MRP producer cells. Evidence of long-term (9 months) gene transfer was provided by PCR of peripheral blood from MRP-transduced mice. Southern blot analysis confirmed the integrity of the provirus in the MRP-transduced mice. Long-term MRP expression (>5 months) was detected by RT-PCR and fluorescence-activated cell sorting of blood from living mice. High-level expression of MRP in murine hematopoietic cells reduces doxorubicin-induced leukopenia and mortality. Furthermore, we show in vivo selection of MRP-transduced cells following doxorubicin administration, with better and more significant chemoprotection after the second chemotherapy cycle. These data indicate that MRP retroviral gene transfer may be useful for chemoprotection and selection.

ATP-Binding Cassette Transporters↗
PubMed1999

Targeting retroviral vectors to CD34-expressing cells: binding to CD34 does not catalyze virus-cell fusion.

We have attempted to engineer murine leukemia virus (MuLV)-based retroviral vectors to specifically transduce cells expressing human CD34, an antigen present on the surface of undifferentiated hematopoietic stem cells. A number of chimeric ecotropic MuLV envelope (Env) proteins were constructed that contained anti-CD34 single-chain antibody variable fragments (scFvs). The scFv-Env proteins were generated either by replacing the receptor-binding domain of Env with the scFv or by inserting the scFv into the N terminus of the Env protein. Only chimeric Env proteins with scFv insertions between amino acids 6 and 7 were incorporated into viral particles, and coexpression of native MuLV Env did not rescue incorporation-defective proteins. In addition, the efficiency of incorporation varied with the specific anti-CD34 scFv that was used. Retroviral vectors containing the scFv-Env proteins bound to CD34+ cells and transduced NIH 3T3 cells expressing human CD34 (3T3-CD34 cells) at approximately twice the efficiency of the parental NIH 3T3 cells. However, the introduction of the mutation D84K, which prevents binding to the ecotropic MuLV receptor mcat-1, prevented transduction of both NIH 3T3 and 3T3-CD34 cells. Complementation cell-cell fusion assays [Zhao et al. (1997). J. Virol. 71, 6967-6972] in 3T3-CD34 cells revealed that although the scFv-Env proteins could contribute postbinding entry functions when bound to mcat-1, they were unable to do so when bound to CD34. Taken together, these data suggest that although the interaction with CD34 effectively increased the concentration of virus on 3T3-CD34 cells, entry could occur only through an interaction with mcat-1; CD34 alone was not capable of triggering the appropriate postbinding changes that lead to viral entry.

3T3 Cells↗
PubMed1999

Clearance kinetics of CD34+ cells from peripheral blood: an independent predictor of hematologic recovery after high-dose chemotherapy and hematopoietic stem cell transplantation.

We measured the concentration of CD34+ cells in peripheral blood (PB) (1/2) h prior to and (1/2), 1, 3, 6, and 12 h following hematopoietic stem cell (HSC) infusion in 34 breast cancer patients treated with high-dose chemotherapy (HDC). The decrease in these concentrations over time enabled us to determine the clearance kinetics of CD34+ cells from PB. The absolute number of CD34+ cells in PB generally peaked at (1/2) h after infusion, then rapidly declined from 1 to 3 h post infusion and continued to fall until 12 h post transplant, but more slowly. In univariate analysis, CD34+cells/kg infused, CFU-GM/kg infused, the CD34+ count at (1/2) h, and the 12-h clearance of CD34+ cells from PB were predictors of hematologic recovery, as were each of the two phases of clearance when the slope was divided into rapid and slow phases (from (1/2) to 3 and from 3 to 12 h post transplant, respectively). We then stratified our population by the number of CD34+ cells/kg infused. In group 1, patients received </=7.5 x 10(6) CD34+ cells/kg; in group 2, >7.5 x 10(6) CD34+ cells/kg. After adjusting for CD34+ cells injected, age, and purged or unpurged graft in multivariate analysis, the 12 h clearance remained a predictor of hematologic recovery in group 1. In addition, the second phase of clearance (from 3 to 12 h after infusion) was an even better predictor than the 12 h clearance. In group 2, however, no statistically significant correlation was observed, even with the number of HSC injected. Results suggest that rapidity of clearance of CD34+cells from PB is an independent indicator of hematologic recovery in patients receiving lower doses of CD34+ cells. When the cell dose injected is over a threshold, PB clearance correlations with hematologic recovery are masked.

Adult↗
PubMed1999

Unreliability of carcinoembryonic antigen (CEA) reverse transcriptase-polymerase chain reaction (RT-PCR) in detecting contaminating breast cancer cells in peripheral blood stem cells due to induction of CEA by growth factors.

RT-PCR is increasingly used for the detection of minimal residual disease in solid tumors. Carcinoembryonic antigen (CEA) RT-PCR seemed to be highly specific for detection of tumor cells when tested on PBMC. A very high frequency of RT-PCR amplification product for CEA in PBSC from breast cancer patients mobilized with G-CSF was found. However, this result contrasted with tumor cell detection by immunocytochemistry (ICC) which showed no correlation with RT-PCR results. In addition, CEA mRNA was amplified in most G-CSF-mobilized PBSC samples derived from patients with hematological malignancies and from healthy donors of allogeneic stem cells, although no circulating epithelial cells could be demonstrated by ICC. CEA RT-PCR expression was observed in PBMC from healthy individuals incubated in vitro with G-CSF. These data suggest that CEA transcription can be induced by G-CSF, resulting in a loss of specificity of CEA RT-PCR for tumor cell detection in PBMC. We conclude, CEA RT-PCR may not be recommended to detect tumor cell contamination in peripheral blood from patients treated with G-CSF. This may have implications on tumor cell detection by RT-PCR in tissues where endogenous or exogenous growth factors may induce the transcription of CEA or other genes.

Breast Neoplasms↗
PubMed1999

The administration of 10 microg/kg granulocyte colony-stimulating factor (G-CSF) alone results in a successful peripheral blood stem cell collection when previous mobilization with chemotherapy and hematopoietic growth factor failed.

Some heavily pretreated cancer patients fail to mobilize enough peripheral blood stem cells (PBSC) after stimulation with chemotherapy and hematopoietic growth factors. For these patients the best way to obtain an adequate PBSC collection is unknown. Here we report 6 heavily pretreated cancer patients who failed to mobilize sufficient PBSC after stimulation with chemotherapy and G-CSF 5 microg/kg/day. In these cases, we used G-CSF 10 microg/kg/day alone for six days at least 3 weeks after the last chemotherapy. After three consecutive leukaphereses starting on day 5, five patients had adequate PBSC collections. With 6 days of G-CSF 10 microg/kg/day alone, 2.8 x 10(6) (+/- 1) CD34+ cells/kg were collected. This was significantly higher than the number of CD34+ cells/kg collected after chemotherapy and G-CSF 5 microg/kg 0.3 x 10(6) (+/- 0.1) [P = 0.05]. Four patients received high-dose chemotherapy with PBSC support. Hematologic recovery observed in these patients was as expected. In conclusion, G-CSF 10 microg/kg alone can mobilize progenitor cells into peripheral blood when previous mobilization with chemotherapy and G-CSF 5 microg/kg fails.

Adult↗
PubMed1998

Anti-CD34+ Fabs generated against hematopoietic stem cells in HIV-derived combinatorial immunoglobulin library suggest antigen-selected autoantibodies.

Bone marrow suppression associated with HIV infection does not appear to be solely due to direct viral cytopathic effects. Autoantibodies may play a role in myelosuppression, however it is unclear whether autoantibodies produced in HIV infection represent a primary pathogenic process or merely reflect polyclonal B cell activation. To address these questions, we generated combinatorial immunoglobulin libraries using the pComb3 phagemid from an HIV+ individual with evidence of circulating autoantibodies. From one library, three anti-CD34 Fabs were identified using fresh CD34+ cells as antigenic targets by a method of phage subtraction. The anti-CD34 Fabs are specific by immunoblotting and Elisa and are of high affinity, with calculated Kds in the range of 10(-7) -10(-8) M. Nucleic acid sequencing revealed all three to be of the VH3 family and to have lambda light chains with some gene segments expressing little somatic mutation, while other segments were somatically mutated in patterns suggestive of antigen selection. These findings indicate that (1) A subset of HIV-associated anti-CD34 autoantibodies are monospecific and antigen-selected and are not merely a consequence of polyclonal B cell activation and elevated Ig levels in HIV. Autoreactivity in HIV therefore includes both polyspecific, low affinity antibodies as well as monospecific antigen-selected high affinity antibodies. (2) Although bone marrow suppression in HIV is likely to be multifactorial, autoantibodies to hematopoietic stem cells may contribute to its pathogenesis. (3) Library sampling of VH gene family rearrangements shows no evidence for under-representation of the VH3 family in the immune dysregulation of HIV infection. Phage subtraction is corroborated to be an effective means of identifying, cloning, and characterizing antibodies to hematopoietic differentiation antigens.

Antibody Affinity↗
PubMed1997

Quantification of CD34+ cells mobilized into the peripheral blood predicts the yield of the leukapheresis product and can replace progenitor assays.

We reviewed 333 concomitant blood and cytapheresis samples from 101 patients with solid malignancies of various histological cell types. All samples were analyzed for CFU-GM, BFU-E and CD34+ determination. We found a good correlation between progenitor assays CFU-GM and CD34+ determination in the blood and cytapheresis (r = 0.77, p < 0.0001 and r = 0.79, p < 0.0001 respectively). The number of CD34+ cells in the peripheral blood was predictive of the CD34+ yield in the cytapheresis (r = 0.86, p < 0.0001), and we determined that a threshold of 26 CD34+/microliter of blood was sufficient to harvest 10(6) CD34+/kg in a single apheresis. Thirty breast cancer patients received injections of peripheral blood stem cells after the same high-dose chemotherapy. For these patients, we found a significant correlation between the quantity of CD34+ cells or CFU-GM collected and both granulocyte and platelet recovery. In conclusion, there is a very good correlation between CFU-GM assays and CD34+ determination and a good correlation between circulating CD34+ cells and the yield obtained by the cytapheresis. The number of CD34+ cells collected is also significantly correlated with hematological recovery. Because CD34+ quantification is an accurate, fast and inexpensive technique, this can lead to the progressive forsaking of progenitor assays in a clinical setting.

Adolescent↗
PubMed1997

[Efficiency of high-dose FEC chemotherapy for the mobilization of hematopoietic stem cells into peripheral blood].

The best regimen for mobilizing hematopoietic stem cells (HSC) into peripheral blood is not yet defined. The efficiency of FEC chemotherapy in the treatment of breast cancer is well established and the effects of FEC on HSC mobilization have been characterized. We tested the feasibility and the toxicity of a high-dose FEC regimen which may improve the mobilizing capacity of conventional FEC. Twenty patients with poor prognosis breast cancer received high-dose FEC and filgrastim 5 micrograms/kg. Three leukaphereses were performed on each patient for 3 consecutive days. Total numbers of CFU-GM and CD34+ cells were assessed, and a retrospective analysis was made. The numbers of CFU-GM/kg and CD34+ cells/kg collected (mean +/- standard error) were respectively 12.2 x 10(5) (+/- 2.4) and 14.6 x 10(6) (+/- 2.5). Extra-hematologic toxicity was negligible. Hematologic recovery after CTCb high-dose chemotherapy and HSC infusion was rapid. High-dose FEC is efficient for collecting HSC in peripheral blood. Extra-hematologic toxicity is weak and hematologic recovery after autograft is normal. Increased dosage of epirubicin and cyclophosphamide could allow a single leukapheresis collection of sufficient HSC from peripheral blood.

Adult↗
PubMed1996

Peripheral blood mononuclear cells from autologous hematopoietic stem cell transplantation recipients produce and respond to IL-12.

Autologous hematopoietic stem cell transplantation effectively results in restoration of hematopoiesis, but induces an often prolonged period of T cell dysfunction including redistribution of T cell subsets and defective T cell proliferation. Because IL-2 production is markedly decreased following autologous stem cell engraftment, and because IL-12 has direct stimulatory effects on TH1 cells, a major source of IL-2, we investigated the production and responsiveness of IL-12 of peripheral blood mononuclear cells (PBMC) of autologous stem cell recipients in the first 6 months following engraftment. When stimulated with S. aureus Cowan I (SAC), PBMC from autologous hematopoietic transplant recipients in the early months following engraftment show no decrease in production of IL-12 as compared to control PBMC. Furthermore, transplant-derived PBMC appear to be functionally responsive to exogenously provided IL-12 as indicated by several criteria. In vitro proliferation of total PBMC and of isolated CD4+ T cells from transplanted recipients to PHA (1 microgram/ml) + IL-12 (20 U/ml) was comparable to controls, excluding the possibility that only NK or CD8+ cells respond to IL-12. Culture of both control and transplant-derived PBMC in PHA + IL-12 (20 U/ml) or IL-2 (100 U/ml) + IL-12 (20 U/ml) combinations yielded comparable production of IFN-gamma, one of the major biological effects of IL-12 in vivo, as well as equal production of TNF-alpha, a costimulatory factor of IL-12-mediated induction of IFN-gamma by NK cells. Taken together, this in vitro evidence suggests that following autologous transplantation, PBMC do not appear to have either decreased production of endogenous IL-12 or defective functional responsiveness to exogenously provided IL-12.

CD4-Positive T-Lymphocytes↗
PubMed1995

Thrombopoietic effects and toxicity of interleukin-6 in patients with ovarian cancer before and after chemotherapy: a multicentric placebo-controlled, randomized phase Ib study.

Recombinant human interleukin-6 (IL-6) has previously been shown to increase platelet counts in normal and sublethally irradiated mice, dogs, and primates. To assess its tolerance and efficacy in clinical use, we performed a randomized phase Ib study in patients with ovarian carcinoma. IL-6 was administered during an initial 7-day cycle before any chemotherapy. Beginning 7 days later, six cycles of chemotherapy containing carboplatin were administered every 3 weeks. During chemotherapy cycles 2 to 6, IL-6 was administered from day 4 through day 17 at escalating dose levels from 0.5 to 10 micrograms/kg/d. At each level, three patients received IL-6 and one patient received a placebo. During the prechemotherapy cycle of IL-6, a dose-dependent increase in platelet count was observed from day 12 to 15 and was maximal on day 15 (r = .77; P < .01). The median ploidy of bone marrow megakaryocytes shifted from 16 N to 32 N after 7 days of the initial prechemotherapy IL-6 administration. Dose-dependent increases in C-reactive protein (CRP) and fibrinogen levels were observed on day 8 (P < .0001 for both). A significant decrease in hemoglobin level occured rapidly after initiation of IL-6 therapy and was maximal on day 8 (P < .001). When given after chemotherapy, IL-6 accelerated platelet recovery after chemotherapy cycles 2 to 6. Postponements of scheduled chemotherapy due to thrombocytopenia were less frequent in patients treated with IL-6. No difference in either neutrophils or peripheral blood progenitor assays was observed during or after IL-6 treatment. Toxicity of IL-6 appeared mild and was not dose-limiting up to 10 micrograms/kg/d. Systemic symptoms such as fever, headache, and myalgia were the main side effects and were easily relieved by acetaminophen administration. No biologic toxicity was observed. The data indicate that IL-6 is a well-tolerated cytokine and capable of accelerating platelet recovery in patients receiving chemotherapy.

Acute-Phase Proteins↗