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Alain Bernard

Publications and source records attributed to Alain Bernard.

At least 19 recordsLinked to original sources
PubMed2007

National standardization of ZAP-70 determination by flow cytometry: the French experience.

BACKGROUND: ZAP-70, after being considered as a potential surrogate for VH mutational status, has seen its own prognostic value emerge. We aimed at standardizing a simple, fast, and reproducible flow cytometry method. METHODS: AntiZAP-70 antibody 2F3.2 was used with indirect labeling and secondary anti-IgG2a antibody. The reference values for the expression of the results were determined on 45 normal blood samples. ZAP-70 protein expression was investigated in 192 CLL samples. The indirect technique was compared with FITC-conjugated 2F3.2 clone, and with clone 1E7.2-FITC, -PE or -AlexaFluor 488. RESULTS: Using FITC or PE-conjugated antibodies, 2F3.2 and 1E7.2 clones allowed a much less adequate discrimination between positive and negative cells and discordant cases were most likely true negative cases. Using the AlexaFluor 488 conjugated 1E7.2 clone, the discordant cases were mostly negative with the conjugated antibody and positive with the 2F3.2 clone but Western blotting or RNA microarray confirmed discordant cases were false negative with the conjugated antibody. Subsequently, recommendations were used by 13 centers participating in an interlaboratory quality control protocol. The use of MFI ratio appeared to be more reliable. CONCLUSIONS: Results suggested that slight differences in the procedure had little impact on the interpretation in characteristic cases; however, careful interpretation was required for values close to threshold.

Antibodies↗
PubMed2006

Evaluation of respiratory muscle strength by randomized controlled trial comparing thoracoscopy, transaxillary thoracotomy, and posterolateral thoracotomy for lung biopsy.

OBJECTIVE: The aim of this study was to demonstrate that the postoperative recovery of respiratory muscle strength is better in patients who undergo video-thoracoscopy than in patients who undergo transaxillary thoracotomy or posterolateral thoracotomy. DESIGN: Randomized controlled trial with three parallel groups. STUDY POPULATION: Eligible patients had undergone wedge resection for lung biopsy in interstitial lung disease or in pulmonary nodule. Twenty-four patients were randomly assigned to one of the three thoracic procedures: eight in the video-thoracoscopy (VT) group, eight in the transaxillary thoracotomy (TT) group, and eight in the posterolateral thoracotomy (PLT) group. MEASUREMENTS: The postoperative respiratory muscle strength was assessed by maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) measured by mouth pressure. Measurements were made the day before the operation and 2, 4, and 30 days after the operation. Changes in postoperative MIP and MEP were expressed as a percentage of preoperative values. RESULTS: The three groups were comparable with respect to age, gender, comorbidity, preoperative spirometry, preoperative MIP, MEP and peak flow, and volume of lung tissue. At 2, 4, and 30 days after the operation, mean MIP were, respectively, 111+/-22%, 119+/-22%, and 124+/-22% in the VT group, 76+/-22%, 109+/-22%, and 127+/-22% in the TT group, and 51+/-22%, 50+/-22%, and 77+/-22% in the PLT group (p<0.0001). At 2, 4, and 30 days after the operation, mean MEP were, respectively, 94+/-15%, 103+/-15%, and 105+/-15% in the VT group, 61+/-15%, 98+/-15%, and 126+/-15% in the TT group, and 62+/-15%, 75+/-15%, and 87+/-15% in the PLT group (p<0.05). CONCLUSIONS: Video-thoracoscopy allows better recovery of respiratory muscle function after surgery than posterolateral thoracotomy. However, at 4 and 30 days after surgery, video-thoracoscopy and transaxillary thoracotomy gave similar results of impairment of respiratory muscle strength.

Adult↗
PubMed2006

CD99 acts as an oncosuppressor in osteosarcoma.

CD99 was recently reported to be under control of the osteoblast-specific transcription factor Cbfa1 (RUNX2) in osteoblasts, suggesting a role in the phato-physiology of these cells. No extensive information is available on the role(s) of this molecule in malignant phenotype, and osteosarcoma, in particular, has never been studied. We report that in 11 different cell lines and 17 clinical samples CD99 expression is either undetectable or very low. Being expressed in the normal counterpart, we tested the hypothesis that CD99 down-regulation may have a role in osteosarcoma development and progression. CD99-forced expression in two osteosarcoma cell lines significantly reduced resistance to anoikis, inhibited growth in anchorage independence as well as cell migration, and led to abrogation of tumorigenic and metastatic ability. Therefore, the molecule acts as a potent suppressor of malignancy in osteosarcoma. CD99 gene transfection induces caveolin-1 up-regulation and the two molecules were found to colocalize on the cell surface. Treatment with antisense oligonucleotides to caveolin-1 abrogates the effects of CD99 on migration. The findings point to an antioncogenic role for CD99 in osteosarcoma, likely through the regulation of caveolin-1 and inhibition of c-Src kinase activity.

12E7 Antigen↗
PubMed2005

Targeting CD99 in association with doxorubicin: an effective combined treatment for Ewing's sarcoma.

CD99 is a 32kDa surface glycoprotein that is involved in the migration of leukocytes, cell-cell adhesion and apoptosis of T cells and Ewing's sarcoma (ES) cells, two cell types with a high level of CD99 expression. Engagement of the molecule induces a rapid death signal that appears to be related to the level of expression of this antigen. The rapid apoptosis induced by agonistic anti-CD99 monoclonal antibodies is of clinical interest in ES, a tumour for which no new drugs have been described as clearly effective in the last 10 years. In this study, we show that an anti-CD99 monoclonal antibody can be used to advantage in association with doxorubicin. Striking effectiveness was observed against local tumours and metastases. No remarkably toxic effects of anti-CD99 monoclonal antibody were found in bone marrow against blood precursors. These results provide the necessary rationale and support for a novel modality of therapeutic intervention, which may have application in the care of patients with ES.

12E7 Antigen↗
PubMed2005

Influence of beta 1 integrin intracytoplasmic domains in the regulation of VLA-4-mediated adhesion of human T cells to VCAM-1 under flow conditions.

The VLA-4 integrin supports static cell-cell, cell-matrix adhesion, and dynamic interactions with VCAM-1. Although functions for well-conserved beta(1) integrin cytoplasmic domains in regulating static cell adhesion has been established, the molecular basis for beta(1) integrin-dependent arrest on VCAM-1 under flow conditions remains poorly understood. We have transfected the beta(1) integrin-deficient A1 Jurkat T cell line with beta(1) cDNA constructs with deletions of the NPXY motifs and specific mutations of tyrosine residues. Deletion of either NPXY motif impaired static adhesion induced by CD2 or CD47 triggering or direct beta(1) integrin stimulation. In contrast, PMA-induced adhesion to VCAM-1 was unaffected by deletion of the NPIY motif and only slightly impaired by deletion of NPKY. Moreover, deletion of the NPIY motif resulted in enhanced rolling and reduced arrest on VCAM-1 under shear flow conditions. In contrast, deletion of the NPKY motif did not alter arrest under flow. Although tyrosine to phenylalanine substitutions within two NPXY motifs did not alter static adhesion to VCAM-1, these mutations enhanced arrest on VCAM-1 under flow conditions. Furthermore, although deletion of the C'-terminal 5 AA of the beta(1) cytoplasmic domain dramatically impaired activation-dependent static adhesion, it did not impair arrest on VCAM-1 under flow conditions. Thus, our results demonstrate distinct structural requirements for VLA-4 function under static and shear flow conditions. This may be relevant for VLA-4 activity regulation in different anatomic compartments, such as when circulating cells arrest on inflamed endothelium under shear flow and when resident cells in bone marrow interact with VCAM-1- positive stromal cells.

Amino Acid Motifs↗
PubMed2005

T and B cell cooperation: a dance of life and death.

In order for the body to develop a good antibody response, B cells need to react intimately with antigen specific T cells. Experimental evidence using hapten-carriers revealed that T and B cells do not recognize the same epitope and this led to the view that the physical contact is mediated by the antigen. Although the modern concept of antigen presentation has changed our perception on how the antigen can bridge both cells, the basic virtues of earlier bridging models remain. Over the past few years, a number of surface ligand-receptor pathways have been described, most of them belonging either to the CD28/B7 Ig or to the TNF/TNFR-like families. These act in concert, whether they are agonist or antagonist, in a timely and spatially organized manner. They form cascades of successive induction and recruitment to ensure that T-B cooperation is closely controlled at all stages of antibody induction.

Animals↗
PubMed2005

Use of a decision analysis model to assess the medicoeconomic implications of FDG PET imaging in diagnosing a solitary pulmonary nodule.

This study assessed the use of positron emission tomography (PET) in identifying and diagnosing solitary pulmonary nodules (SPNs). For this a decision analysis model was constructed, and three alternatives were compared: wait and watch (WW), PET and anatomical computed tomography (PET), and CT plus PET (CT+PET). Transition probabilities were estimated from published data and consultations with experts. Costs of diagnosis were derived from the French reimbursement scale, and treatment costs from a national hospital database of diagnosis-related groups. The base case was defined as a 65-year-old male smoker with a 2-cm SPN and an associated high risk of malignancy of 43%. Evaluation criteria included incremental cost-effectiveness ratios and the proportion of unnecessary operations avoided in patients without malignant SPN. For the base case WW was the least effective and cheapest strategy. CT+PET was more effective and presented lower incremental cost-effectiveness ratio ( 3,022 per life-year gained). It also was superior to PET in cost-effectiveness terms and resulted in 4.3% fewer unnecessary resections of benign SPN than did PET. Risk profile analyses performed on SPN malignancy risk showed that CT + PET remains the most cost-effective strategy in the range of 5.7-87%, and that WW is more cost-effective in the range of 0.3-5.0%. CT+PET is thus cost-effective in detecting malignant SPN in patients with a risk of malignity of at least 5.7% and may avoid inappropriate resections of benign SPN. These findings support the attempts to introduce a larger number of PETs in France for SPN diagnosis.

Aged↗
PubMed2005

Analytical variability of the Fibrotest proteins.

OBJECTIVES: The analytical variability of the Fibrotest (FT) parameters raises the issue of the test's reliability for routine use. Whereas standardization has been proposed by the International Federation of Clinical Chemistry (IFCC) for specific proteins, few data are available concerning the actual transferability of the FT proteins, i.e. haptoglobin, apolipoprotein A1 and alpha2 macroglobulin. The aim of this study was to evaluate the analytical variability of the FT proteins. DESIGN AND METHODS: During the FIBROPACA study, we evaluated 112 sera from patients with hepatitis C infection who underwent liver biopsy. We compared measurements of haptoglobin, apolipoprotein A1 and alpha2 macroglobulin by the autoanalyzers Immage (Beckman-Coulter) and the FT reference BNProspec (Dade-Behring). RESULTS: Optimal concordance was found for haptoglobin (correlation: y = 1.05x -0.09; correlation coefficient = 0.98). However, apolipoprotein A1 as determined with Immage was globally 12% lower than with BNProspec (correlation: y = 0.88x -0.05; correlation coefficient = 0.91) and alpha2 macroglobulin values were 40% greater with Immage than with BNProspec (correlation: y = 1.40x -0.46; correlation coefficient = 0.96). CONCLUSIONS: Inter-technique analytical variability of the Fibrotest parameters remains a major issue. After IFCC standardization of specific proteins, some discrepancies remain for alpha2 macroglobulin and, to a lesser extent, for apolipoprotein A1. National and international quality control programs would be useful to monitor analytical performance of protein assays.

Apolipoprotein A-I↗
PubMed2004

Arachidonic acid relaxes human pulmonary arteries through K+ channels and nitric oxide pathways.

We aimed to investigate the role of K(+) channels and nitric oxide (NO) on the relaxant effects of arachidonic acid in the human intralobar pulmonary arteries. Arachidonic acid produced a concentration-dependent relaxation (E(max)=93+/-3% of maximal relaxation induced by papaverine 0.1 mM;-log EC(30)=7.03+/-0.09) that was antagonized by the cyclooxygenase inhibitor indomethacin (1 microM), by the combination of cyclooxygenase blockade and cytochrome P450 (CYP) blockade with 17-octadecynoic acid (17-ODYA, 10 microM), by the combination of cyclooxygenase inhibition and NO synthase (NOS) inhibition with N(omega)-nitro-l-arginine (l-NOARG, 100 microM), by the simultaneous inhibition of CYP and NOS and by the simultaneous blockade of cyclooxygenase, CYP and NOS. Arachidonic acid-induced relaxation was significantly inhibited by glibenclamide (1 microM, ATP-dependent K(+) channel (K(ATP)) blocker), apamin and charybdotoxin (0.3 microM small (SK(Ca)) and 0.1 microM big (BK(Ca)) conductance Ca(2+)-sensitive K(+) channel blocker, respectively), and 4-aminopyridine (1 mM, voltage-dependent K(+) channel (K(V)) blocker). Indomethacin and ketoconazole suppressed the antagonistic effects of glibenclamide and apamin and 17-ODYA those of all the K(+) channel blockers tested. l-NOARG suppressed only the antagonistic effect of glibenclamide. We suggest that K(ATP), SK(Ca), BK(Ca) and K(V) are involved in the arachidonic acid-induced relaxation of human pulmonary arteries. Cyclooxygenase metabolites are the main relaxing agents of arachidonic acid, involving K(ATP) and SK(Ca) channels. CYP-dependent metabolites modulate arachidonic acid-induced relaxation through a pathway involving K(+) channels. K(ATP) channels are involved through a NOS-dependent pathway.

Arachidonic Acid↗
PubMed2004

Molecular mechanisms of CD99-induced caspase-independent cell death and cell-cell adhesion in Ewing's sarcoma cells: actin and zyxin as key intracellular mediators.

CD99 is a unique 32-kDa cell surface molecule with broad cellular expression but still poorly understood biological functions. In cancer cells, CD99 is highly expressed in virtually all Ewing's sarcoma (ES). Engagement of CD99 induces fast homotypic aggregation of ES cells and caspase-independent apoptosis. In this study, we analysed signal transduction after CD99 engagement on ES cells. Findings obtained with selective inhibitors indicated that only actin cytoskeleton integrity was essential for cell-cell adhesion and apoptosis of ES cells. Indeed, CD99 stimulation induced actin repolymerization, further supporting the role of cytoskeleton in CD99 signaling. Gene expression profiling of ES cells after CD99 engagement showed modulation in the expression of 32 genes. Among the pool of upregulated genes reported to be involved in cell adhesion, we chose to analyse the role of zyxin, a cytoplasmic adherens junction protein found to play a role in the regulation of the actin cytoskeleton. Overexpression of zyxin after CD99 ligation was confirmed by real-time PCR and Western blot. Treatment of ES cells with zyxin antisense oligonucleotides inhibited CD99-induced cell aggregation and apoptosis, suggesting a functional role for this protein. Therefore, our findings indicate that CD99 functions occur through reorganization of cytoskeleton and identify actin and zyxin as the early signaling events driven by CD99 engagement.

Actins↗
PubMed2004

Mature human thymocytes migrate on laminin-5 with activation of metalloproteinase-14 and cleavage of CD44.

We have previously shown that laminin-5 is expressed in the human thymic medulla, in which mature thymocytes are located. We now report that laminin-5 promotes migration of mature medullary thymocytes, whereas it has no effect on cortical immature thymocytes. Migration was inhibited by blocking mAbs directed against laminin-5 integrin receptors and by inhibitors of metalloproteinases. Interactions of thymocytes with laminin-5 induced a strong up-regulation of active metalloproteinase-14. However, we found that thymocytes did not cleave the laminin-5 gamma(2) chain, suggesting that they do not use the same pathway as epithelial cells to migrate on laminin-5. Interactions of thymocytes with laminin-5 also induced the release of a soluble fragment of CD44 cell surface molecule. Moreover, CD44-rich supernatants induced thymocyte migration in contrast with supernatants depleted in CD44 by immunoadsorption. CD44 cleavage was recently reported to be due to metalloproteinase-14 activation and led to increased migration in cancer cells. Thus, in this study, we show that laminin-5 promotes human mature thymocyte migration in vitro via a multimolecular mechanism involving laminin-5 integrin receptors, metalloproteinase-14 and CD44. These data suggest that, in vivo, laminin-5 may function in the migration of mature thymocytes within the medulla and be part of the thymic emigration process.

Cell Adhesion Molecules↗
PubMed2004

Apoptosis of naive CD4+ T-cells from HIV-infected patients with poor immune response to HAART is enhanced in vitro by steroid.

OBJECTIVE: Because the absence of immune restoration in HIV-infected patients efficiently treated by highly active antiretroviral therapy (HAART) may be due to excessive immune activation, we prospectively studied the effect of hydrocortisone on T-cell apoptosis in a cohort of patients with satisfactory virologic response. METHODS: Apoptosis of T-cell subsets including naïve CD45RA(+)CD4+ T-cells was determined at baseline and at months 1 and 3 after initiation of HAART. A satisfactory immune response was defined as an increase >100/microL CD4+ T-cells at month 3 compared to baseline. RESULTS: Twenty out of 63 patients showed undetectable viral load at month 3, among whom eight exhibited a satisfactory immune response. Down-regulation spontaneous CD4+T-cell apoptosis was significant in the group of patients with a satisfactory immune response compared to the other patients. However, hydrocortisone up-regulated apoptosis of naïve CD4+ CD45RA+ T-cells, specifically in group of patients with poor immune response, whatever the time point considered: percentage of apoptotic CD4 T-cells was 16+/-16% without hydrocortisone and 22+/-22% with hydrocortisone at month 1, and respectively, 10+/-9 and 17+/-15% at month 3 (P < 0.05) Hydrocortisone had no impact on CD8+ T-cell apoptosis, whatever the considered group. CONCLUSION: Our results suggest to not use steroid therapy as adjuvant immunotherapy in patients with less than optimal immunologic response to HAART.

Adult↗
PubMed2004

Argonaute 3D: a real-time cooperative medical planning software on DSL network.

Today, diagnosis of cancer and also therapeutic choice imply many specialized practitioners. They are generally located at different places and have to take the best decision as promptly as possible with the difficulty of CT-scan or MRI interpretation. Argonaute 3D is a tool that easily overcomes these issues, thanks to a cooperative solution based on virtual reality. An experimentation, where four practitioners met virtually throughout France, allowed to assess the interest of this solution.

Computer Communication Networks↗
PubMed2003

Proteolytic regulation of Forkhead transcription factor FOXO3a by caspase-3-like proteases.

Forkhead family transcription factors are critical regulators of cell cycle progression and apoptosis in hematopoietic cells. Here, we show that FOXO3a (also known as FKHRL1) is a new substrate of caspase-3-like proteases during apoptosis in T lymphocytes. FOXO3a was cleaved in vivo by caspases in leukemic Jurkat cells following engagement of Fas (CD95) receptor, staurosporine, and etoposide treatment, but not following engagement of CD99, a caspase-independent cell death inducer. Caspase-mediated cleavage of FOXO3a was also observed in CD4+ peripheral T cells subjected to activation-induced cell death. The expression of the death adapter FADD and caspase-8 was required for Fas-induced FOXO3a cleavage, but activation of survival pathways by overexpression of FLICE-inhibitory protein or phorbol myristate acetate treatment prevented it. FOXO3a was cleaved in vitro by caspase-3-like proteases at the consensus sequence DELD304A, releasing the N-terminal DNA-binding domain of FOXO3a from its C-terminal transactivating domain. Whereas full-length FOXO3a enhanced Forkhead response element-dependent transcription and apoptosis in Jurkat cells, both fragments were inactive to promote gene activation and cell death. In contrast, a caspase-resistant FOXO3a mutant exhibited enhanced transcriptional and proapoptotic activities. Together, these results indicate that the proteolytic cleavage of FOXO3a by caspases may represent a novel regulatory mechanism of FOXO3a activity during death receptors signaling.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Apoptosis and proliferation kinetics of T cells in patients having experienced antiretroviral treatment interruptions.

Multiple failures of antiretroviral treatments, as a result of multidrug-resistant virus, have led to a proposal for structured therapeutic interruptions (STI). However, a significant decrease in CD4+ T cells may occur. The aim of our study was to determine the kinetics of T cell subpopulation changes, T cell apoptosis and peripheral blood mononuclear cell proliferation after STI. The impact of resistance mutation disappearance on T cell apoptosis was also studied. Ten patients were enrolled prospectively, and blood sampling was performed at weeks 0, 2, 4, 6, 8 and 12. The mean increase in viral load was 1.3 log(10) copies/ml, ranging from 0.1 to 3.2. CD4+ T cell count decreased to a mean of 80 cells/mm(3) from baseline to week 12. In the same period, CD8+ T cells decreased to a mean of 139 cells/mm(3). A significant increase in both T cell apoptosis and proliferation of mononuclear cells was observed. However, proliferation was an early and brief event. The increase in CD4+ T cell apoptosis was obvious in patients exhibiting complete reversion of resistance mutations to antiviral drugs. Our results suggest that during STI, apoptosis is an overwhelming phenomenon compared with proliferation, and may explain the limited immunological impact of this therapeutic option.

Antiretroviral Therapy, Highly Active↗
PubMed2003

CD47 and the 19 kDa interacting protein-3 (BNIP3) in T cell apoptosis.

CD47 is a surface receptor that induces either coactivation or apoptosis in lymphocytes, depending on the ligand(s) bound. Interestingly, the apoptotic pathway is independent of caspase activation and cytochrome c release and is accompanied by early mitochondrial dysfunction with suppression of mitochondrial membrane potential (Deltapsim). Using CD47 as bait in a yeast two-hybrid system, we identified the Bcl-2 homology 3 (BH3)-only protein 19 kDa interacting protein-3 (BNIP3), a pro-apoptotic member of the Bcl-2 family, as a novel partner. Interaction between CD47 and the BH3-only protein was confirmed by immunoprecipitation analysis, and CD47-induced apoptosis was inhibited by attenuating BNIP3 expression with antisense oligonucleotides. Finally, we showed that the C-terminal domain of thrombospondin-1 (TSP-1), but not signal-regulatory protein (SIRPalpha1), is the ligand for CD47 involved in inducing cell death. Immunofluorescence analysis of CD47 and BNIP3 revealed a partial colocalization of both molecules under basal conditions. After T cell stimulation via CD47, BNIP3 translocates to the mitochondria to induce apoptosis. These results show that the BH3-dependent apoptotic pathways, previously shown to be activated by intracellular pro-apoptotic events, can also be turned on by surface receptors. This new pathway results in a fast induction of cell death resembling necrosis, which is likely to play an important role in lymphocyte regulation at inflammatory sites and/or in the vicinity of thrombosis.

Antigens, CD↗