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Biomedical subjects

S Dumont

Publications and source records attributed to S Dumont.

35 records · Page 2Linked to original sources
PubMed1994

Large scale isolation of human blood monocytes by continuous flow centrifugation leukapheresis and counterflow centrifugation elutriation for adoptive cellular immunotherapy in cancer patients.

The increasing interest in mononuclear phagocytes for adoptive cellular immunotherapy (ACI) trials in cancer patients led us to define a procedural approach to harvest reproducibly highly purified single-cell suspensions of large numbers of functional human circulating blood monocytes (Mo). A semiclosed counterflow centrifugal elutriation (CCE) system has been developed, using a new large capacity Beckman JE 5.0 rotor with one interchangeable 40 ml or 5 ml separation chamber, to purify Mo from mononuclear cell (MNC) concentrates of healthy donors and cancer patients obtained by continuous flow centrifugation leukapheresis (CFCL). This method does not require a Ficoll density gradient centrifugation step. A total of 115 leukapheresis procedures were carried out in 35 patients and in 30 healthy donors by either Cobe 2997 or Cobe Spectra, with a similar efficiency in MNC apheresis. The average yield per leukapheresis procedure was 5.6 x 10(9) MNC of purity 90-100% (25-45% Mo, 40-65% lymphocytes). The average yields per elutriation procedure (R/O fraction) were 1.1 x 10(9) cells (purity 93% Mo) using the 5 ml separation chamber, and 1.5 x 10(9) cells (purity 91%) using the 40 ml separation chamber, with a respective recovery of 82 +/- 7% and 78 +/- 8% Mo. In vitro analysis of the viability and function of the purified Mo shows that neither morphological integrity nor physiological activity was compromised by this two-step isolation procedure, which additionally provides highly purified human Mo suspensions, in a quantity suitable for ACl of cancer patients.

Cell Separation↗
PubMed1994

Antitumoral potential of aerosolized interferon-gamma in mice bearing lung metastases.

Cytokines and immune cells are likely to be involved in the control of lung metastasis. We have therefore investigated the possibility of inhibiting lung metastases by the means of interferon-gamma (IFN-gamma) aerosolizations in a murine model of lung cancer. A Lewis lung carcinoma (3LL) was inoculated in the thigh of C57BL/6 mice. Randomized groups of 10 mice each were then treated by repeated aerosols of IFN-gamma (4,000 U/mouse) of aerosols of a Hanks' solution as controls. When the animals were killed at 18 days, the number of lung metastatic nodules was significantly reduced (by 50%; P < 0.01) after IFN-gamma aerosols, compared with controls. When the primary tumor was resected at 18 days and aerosols were continued, in the absence of local recurrence, mice treated by IFN-gamma aerosols survived longer than did controls (P < 0.05). In vitro, IFN-gamma exerted no direct antitumoral effect on 3LL cells in culture. Macrophages recovered from mice receiving IFN-gamma aerosols showed a higher antiproliferative effect on 3LL cells in vitro than did controls. Nevertheless, the higher antiproliferative effect of activated macrophages seems insufficient to explain the difference of survival that we observed between IFN-gamma-treated mice and controls.

Administration, Inhalation↗
PubMed1993

Conserved cysteine residues are critical for the enzymatic function of the lymphocyte-specific tyrosine protein kinase p56lck.

We have evaluated the possibility that conserved cysteine residues are critical for the enzymatic function of p56lck. Through oligonucleotide-directed mutagenesis, 5 Lck residues (cysteines 217, 224, 378, 464, and 475) were individually mutated to alanines, and the effects of these substitutions were tested in various in vitro and in vivo assays. We found that mutation of either of 2 cysteines located in the carboxyl portion of the kinase domain (cysteines 464 and 475) abolished the catalytic function of Lck. In addition, it was noted that alteration of cysteine 475 resulted in a dramatic reduction of the half-life of p56lck. These cysteine residues are highly conserved throughout the tyrosine protein kinase family, suggesting that they may play important functions in catalysis and/or substrate recognition.

Alanine↗
PubMed1992

In vitro glycated low-density lipoprotein interaction with human monocyte-derived macrophages.

Human low-density lipoprotein (LDL) was glycated in vitro (5 days, glucose 50 mmol/l), labelled with 125I, and its binding and uptake by human monocyte-derived macrophages studied. Glycation produced lower binding and lower uptake. Competition experiments using unlabelled LDL (control, glycated, and acetyl-LDL) showed that most glycated LDL was taken up by the apolipoprotein-B100: E receptor pathway. Results suggest that less of the glycated LDL may enter the cells via scavenger receptors, and very minute amount via non-saturable receptor-independent pathways.

Binding, Competitive↗
PubMed1991

Phase I trial of intravenous infusion of ex-vivo-activated autologous blood-derived macrophages in patients with non-small-cell lung cancer: toxicity and immunomodulatory effects.

The purpose of this phase I study was to evaluate the toxicity and biological activity of autologous blood-derived macrophages activated ex-vivo with recombinant human interferon gamma (rhuIFN gamma) [monokine-activated killer (MAK) cells] and administered intravenously to 11 lung cancer patients once a week for 6 consecutive weeks. Peripheral blood monocytes were collected by leukapheresis and then purified by counterflow elutriation. The MAK cells were generated by culturing the purified monocytes in Teflon bags for 7 days and adding rhuIFN gamma to the cultured cells for the last 18 h. These MAK cells expressed differentiation-associated surface antigen MAX1, and were cytotoxic in vitro against tumour cell line U937. The MAK cells were infused at dose levels from 1 x 10(7) to 5 x 10(8) on an intrapatient dose-escalating schedule. No severe adverse side-effects occurred. Toxicity was mild to moderate [primarly fever (75%) and chills (32%)], non-dose-dependent, and non-cumulative. No consistent change in haemostatic function, or liver or renal function was observed. Dose-limiting toxicity was not reached at 5 x 10(8) cells (optimal dose reproduced for each patient). The maximum tolerated dose was not determined. The immunomodulatory activity of i.v. infused MAK cells was demonstrated both in vivo by significant increases in granulocyte count and neopterin level in the patients' peripheral blood post-infusion and in vitro by secretory products (IL-1. TNF alpha, neopterin, and thromboplastin-like substance) in the culture supernatants. The in vivo traffic patterns of autologous MAK cells labelled ex-vivo with 111In oxine were studied in 7 patients. Gamma imaging showed an immediate but transient lung uptake (less than 24 h), and a progressive uptake of radioactivity in the liver and spleen was seen from 6 h to 72 h post-infusion. Our results indicate that the preparation of high numbers of autologous, blood-derived MAK cells is a feasible procedure, and their transfusion is safe for patients. This immunotherapeutic approach seems to be encouraging from the point of view of establishing an adjuvant therapeutic modality in cancer patients with minimal residual disease.

Aged↗
PubMed1991

Activation of human monocytes by Streptococcus mutans serotype f polysaccharide: immunoglobulin G Fc receptor expression and tumor necrosis factor and interleukin-1 production.

Streptococcus mutans serotype f polysaccharide (poly f) was prepared from S. mutans whole cells by autoclaving. The poly f was purified by chromatography on DEAE Trisacryl M and Bio-Gel P100, treated with insoluble pronase, and resubjected to chromatography on DEAE Trisacryl M. Normal human blood monocytes, stimulated in vitro with purified poly f, produced extracellular tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) in a dose-dependent fashion as determined by a heterologous two-site sandwich enzyme-linked immunosorbent assay. Poly f also increased the expression of monocyte cell surface receptors for the Fc part of human immunoglobulin G, activity which is correlated with an increase of the phagocytic activity of the stimulated monocytes. Polymyxin B had no effect on TNF-alpha and IL-1 beta release. Neutralization assays with anti-recombinant human TNF-alpha and anti-recombinant human IL-1 beta immunoglobulin G confirmed the fact that the cytotoxic and mitogenic mediators released by the poly f-stimulated monocytes were mainly TNF-alpha and IL-1 beta.

Antigens, Differentiation↗
PubMed1991

Apheresis-elutriation program for adoptive immunotherapy with autologous activated monocytes in cancer patients.

Human blood monocytes (Mo) and monocyte-derived macrophages (M phi) are known to be potent antitumor cytotoxic effector cells through activation with recombinant human interferon gamma (rIFN-gamma), bacterial muramyldipeptide or the synthetic derivative muramyltripeptide phosphatidylethanolamine entrapped in liposomes (L-MTP-PE). Large-scale generation of ex vivo activated Mo from the blood of cancer patients proved feasible. We report our experience with a fixed rotor speed counterflow centrifugation elutration (CEE) procedure using the newly available Beckman high capacity JE-5.0 rotor system that reproducibly isolates up to 1.0-1.5 x 10(9) Mo with greater than 90% purity, in suspension and functionally intact derived from peripheral blood mononuclear cell-enriched suspensions obtained by leukapheresis (LP) from healthy volunteers and cancer patients. The semiclosed, easy to handle CCE system, was adapted to a sterile technique that permitted clinical trials in adoptive monocyte immunotherapy. Freshly isolated Mo did not lose morphological or functional integrity and had no spontaneous activation. Their abilities to become activated to the cytotoxic state after 18-h stimulation with 500 U/ml rIFN-gamma or 1 microgram/ml L-MTP-PE and to differentiate into matured M phi in vitro were not altered. The system was therefore used to isolate large numbers of Mo for a phase I clinical trial of intraperitoneal immunotherapy with L-MTP-PE activated autologous Mo in nine patients with peritoneal carcinomatosis. Each patient received weekly Mo infusions (n = 5) with an intrapatient dose escalation schedule (from 10(7) to 10(9) Mo). Toxicities were mild including fever, chills and abdominal pain. There was no treatment-induced thromboembolic event or capillary leak syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1988

Establishment and characterization of long-term cultured cell lines of murine resident macrophages.

Murine resident macrophages can proliferate in vitro when they are grown in coculture on a layer of mesothelial or endothelial type feeder cells. Resident macrophages were obtained from lung explants of C57Bl/6 lpr/lpr mice and from spleen explants or peritoneal washing of Balb/c mice; the cells were seeded without further washing. After 3-4 weeks of culture, the macrophages began to proliferate on a confluent layer of feeder cells. The macrophages then could be collected in the fluid phase and reseeded for permanent culture after generation of a new feeder layer. These cells were characterized as macrophages by the following criteria: 1) their morphology, ultrastructure, and adherence properties; 2) more than 90% of the macrophages phagocytized yeasts compared with less than 1% of the feeder cells; 3) the presence of functional Fc and mannose receptors, nonspecific cytoplasmic esterases, and membrane ectoenzymes such as nicotinamide adenine dinucleotide (NAD) glycohydrolase and nucleotide pyrophosphatase; 4) by cytofluorographic phenotype analysis with monoclonal antibodies, characterizing a normal macrophage population (MAC1+, Fcrec+, H-2K+, THY1-, LYT2-, L3T4-). 5) by functional studies proving that the expanded macrophages could function as accessory cells in the induction of lymphocyte proliferation in response to concanavalin A (Con A), that they generated reactive oxygen radicals and that they were cytotoxic for tumor cells. During coculture, growth or activating factors such as macrophage colony-stimulating factor or gamma-interferon were released in the medium. Long-term cultured macrophages had chromosomal abnormalities. Our study suggests that tissue macrophages can proliferate in vitro and hence that it is possible to establish long-term cultured cell lines of macrophages of defined and reproducible characteristics.

Animals↗
PubMed1988

Control of the antitumoral activity of human macrophages produced in large amounts in view of adoptive transfer.

Purified human blood monocytes were grown in hydrophobic bags in RPMI medium containing additional amino acids, indomethacine and growth factors. Autologous serum was added after a few days of culture at 37 degrees C, 5% CO2. The antitumoral activity generated by activated monocytes against human tumor cells grown in vitro was mediated by soluble effectors in contrast to macrophages which acted by cell contact. Monocyte differentiation into macrophages was achieved after 7 days of culture and characterized by phagocytosis and expression of MAX 1 antigen and non-specific esterases. The macrophages remaining in suspension in the bags were activated by exposure to immunostimulating compounds used alone or in combination (recombinant human gamma-interferon and muramyldipeptide). Activated macrophages were cytotoxic in vitro against U 937 or ovary carcinoma tumor lines (95% cytotoxicity) at a 1/1 effector/tumor cell ratio. The antitumoral potency of activated macrophages was confirmed in vivo where adoptive transfer of one million human macrophages twice a week to nude mice bearing human ovary carcinoma caused a marked regression of the primary tumor.

Animals↗
PubMed1988

Immunotherapy of cancer: experimental approach with activated macrophages proliferating in culture.

Murine macrophages isolated from the peritoneal cavity or from the lung were continuously grown and expanded in vitro on a confluent layer of "mesothelial or endothelial" feeding cells. These cell lines could be obtained from C57B16 or BalbC mice and were nontumorogenic in nude mice. The macrophages were characterized by their capacity to phagocytose yeasts and by the presence of nonspecific esterases, of Fc receptors, and of specific antigens (MAC1 ...). In vitro, these macrophages were fully activated and were tumoricidal against different tumor cell lines. In vivo, adoptive transfer of the expanded macrophages to mice bearing EMT6 sarcoma or 3LL metastasizing carcinoma inhibited the growth of the primary tumors and the development of metastases. Local injection in the vicinity of the primary tumor and i.v. transplantation were effective. The adoptive transfer of expanded macrophages could lead to a new kind of immunotherapy of neoplastic diseases combining selective amplification with effective activation of macrophages as key effector cells.

Animals↗
PubMedDate not supplied

Effect of ammonia on endocytosis and cytokine production by immortalized human microglia and astroglia cells.

Ammonium acetate decreased in a concentration-dependent manner the phagocytic uptake of mannosylated latex microspheres and of yeast by immortalized human microglia (CHME-5) and astroglioma (GL-15) cells. In both cell lines ammonium acetate affected also the secretion of certain cytokines. The most conspicuous effects were the following: in both cell lines ammonium acetate enhanced greatly the secretion of tumor necrosis factor-alpha in the absence of any other stimulus. in the human microglia cells ammonia decreased the constitutive secretion of interleukin-6, but it enhanced the stimulated (interleukin-1 alpha, tumor necrosis factor-alpha, gamma-interferon and gamma-interferon + tumor necrosis factor-alpha) secretion of interleukin-8. In the astroglioma cell line, the stimulated release of tumor necrosis factor-alpha, interleukin-6 and interleukin-8 was diminished by ammonium acetate. The magnitude of the ammonia-effect depended on the stimulating agent (lipopolysaccharide, interleukin-1 alpha, tumor necrosis factor-alpha, gamma-interferon). The results are discussed with regard to their potential importance in the pathogenesis of human diseases with elevated blood and brain ammonia concentrations.

Acetates↗
PubMedDate not supplied

[Reintegration to work in persons having survived a myocardial infarction: current review and ways of development for clinical interventions].

The main purpose of this article is to update the state of knowledge regarding work reintegration following myocardial infarction. Occupational perspectives have greatly evolved during the second half of this century. This can be attributed mainly to a better understanding of the pathology itself and to a development of new therapeutic avenues which are part of a more global vision of the bio-psycho-social characteristics of the patient. The authors did not intend to realize an extensive review of the literature on the subject, but analysed the most significant articles published over the past 20 years. They were selected because of their frequent citation on the scientific literature which seems to confirm their significance and credibility. Following the analysis of the articles selected, the authors conclude that the scientific community has reached a consensus to the effect that the general evolution of the patient post myocardial infarction is greatly determined by psychosocial factors. It follows that comprehensive rehabilitation programs despite their limited impact in an experimental setting offer some stimulating perspectives. They suggest that some research effort be oriented towards the evaluation of the actual long term outcomes of rehabilitative programs especially on quality of life in general and on quality of life at work more specifically.

Employment↗
PubMedDate not supplied

Study of the dependence of human monocytes and macrophages antitumoral properties upon TNF-alpha expression or release.

This study compares the antitumoral properties of isolated circulating human blood monocytes (Mo) and of mature macrophages (MO) obtained by 7 days differentiation of Mo or isolated from alveolar washing. These cells were activated to cytotoxicity in the presence of recombinant human interferon-gamma (rHuIFN-gamma). This antitumoral effect was measured at a low (1/1) effector/target ratio without pretreatment of the tumor cells. Activated Mo released tumor necrosis factor-alpha (TNF-alpha) in the culture medium where their antitumoral activity could be totally neutralized by specific anti-rHuTNF-alpha antibodies. In contrast, blood monocytes derived macrophages differentiated and activated in vitro expressed TNF-alpha on their membrane where it could be labelled and partially neutralized by anti-rHuTNF-alpha antibodies. Direct effector/target contact was required for the activity of macrophages differentiated in culture or collected from the lung cavity of healthy subjects. When these macrophages were obtained from infected patients or subjected to LPS treatment, they directly released cytotoxic amounts of TNF in the extracellular fluid after activation with IFN-gamma. Monocytes act mainly by soluble mediators (TNF-alpha being a key factor), while differentiated macrophages in the absence of endotoxin act by close cell to cell contact involving the lytic action of membranous TNF-alpha as well as some release of soluble TNF-alpha. We also present evidences (based on the use of various protease inhibitors) that the role of proteases is much less crucial in the cytotoxic action of monocytes and macrophages.

Cytotoxicity, Immunologic↗
PubMedDate not supplied

Antitumoral properties and reduced toxicity of LPS targeted to macrophages via normal or mannosylated liposomes.

Neo-mannosylated liposomes have been prepared by coupling a mannose derivative bearing a hydrophilic spacer arm to preformed large unilamellar liposomes containing 4-(p-maleimidophenyl) butyryl-phosphatidylethanolamine. Lipopolysaccharide (LPS) was encapsulated in normal or neo-mannosylated liposomes; the neo-mannosylated vesicles showed specificity for the in vitro activation to toxicity of macrophages only in the case of differentiated macrophages presenting mannose receptors at their surface. In vivo, LPS entrapped in neo-mannosylated vesicles showed a reduced toxicity for animals hypersensitive to LPS. Moreover targeting of LPS to tissue macrophages with neo-mannosylated liposomes induced regression of experimental solid tumors in mice (EMT6 sarcoma, 3LL carcinoma) and was effective on lung metastases.

Animals↗