Search PubMed⌕ Search

Biomedical subjects

F Vincent

Publications and source records attributed to F Vincent.

At least 109 records · Page 6Linked to original sources
PubMed1992

Immunophenotypic characterisation of human peritoneal and alveolar macrophages and of human blood monocytes differentiated in the presence of either GM-CSF or M-CSF or a combination of GM-CSF/M-CSF.

In vivo, circulating blood monocytes (Mo) migrate into the various tissues where they undergo terminal maturation into macrophages (M phi) with morphological and sometimes functional properties that are characteristic for the tissue in which they reside. This tissue-specific M phi heterogeneity results from the immediate microenvironment, but may also originate from genetically distinct Mo subpopulations. The in vitro transformation of Mo to M phi is thought to reflect the events of the in vivo maturation and thus is widely used as a model to analyse M phi development. To study the heterogeneity within the mononuclear phagocyte system, we have investigated the phenotypic characterisation of mature tissue M phi, blood Mo and Mo-derived M phi cultured in medium with either GM-CSF, M-CSF or a combination of both cytokines. Tissue peritoneal and alveolar M phi showed different antigenic specificities, particularly concerning the transferrin receptor and CD68 and CD14 antigens. M-CSF-derived M phi when compared to the other M ø populations also exhibited a significantly increased expression of transferrin receptor and CD68 antigen. In contrast, GM-CSF treated cells which exhibited a better long term survival, showed notably more positivity for CD11b and CD32 antigens. These results show that the phenotypic heterogeneity of the different M phi populations is limited and appears to result from discrepancies in the differentiation and/or activation of the cells. The location of the CD68 antigen, which is generally considered to be an intracellular protein, was investigated at the ultrastructural level and found to be exclusively situated at the outer cell membrane.

Antibodies, Monoclonal↗
PubMed1992

Human blood-derived macrophages: differentiation in vitro of a large quantity of cells in serum-free medium.

Large quantities of human blood-derived monocytes have been cultured in suspension in nonadherent cell culture bags and maintained for up to 3 weeks in a serum-free medium. This serum-free medium contained Iscove's modified Dulbecco's medium (IMDM) supplemented with human albumin, alpha-phosphatidylcholine, transferrin, and insulin. Morphology, cell surface antigens, and functional properties of these in vitro maturing macrophages were studied in comparison with macrophages cultured in a standard medium containing 10% fetal calf serum. In this report we demonstrate that this serum-free medium allows a better yield of cell survival than the standard medium; it also allows the differentiation of blood monocytes into fully functional macrophagic cells that express the different antigens found in mature macrophages. The results indicate that the use of serum-free defined medium offers good conditions in which to culture large numbers of human monocytes and allows an accurate analysis of the effect of supplementation with growth factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF) on the differentiation and survival of monocytes and macrophages. Serum-free cultures could also be helpful for the precise analysis of the cell secretion activity and for determining the factors that are responsible for monocyte maturation into macrophages.

Antigens, Surface↗
PubMed1991

Long term cultures of human monocytes in vitro. Impact of GM-CSF on survival and differentiation.

In vitro differentiation of human monocytes (Mo) provides large amounts of mature and functionally competent macrophages (M phi) which may be used as potentially powerful anticancer agents for adoptive immunotherapy. Granulocyte macrophage-colony stimulating factor (GM-CSF) was evaluated for its ability to influence long term cultures of Mo-derived M phi. Large quantities of Mo isolated by leukapheresis and elutriation were cultured in non-adherent cell culture bags or in plastic flasks with or without GM-CSF. At various stages of differentiation, GM-CSF treated M phi were recovered and assayed for survival, morphology, surface antigens, functional properties and proliferation in comparison with control M phi. In the present paper, we demonstrate that GM-CSF at a concentration of 50 U/ml (5 ng/ml) promotes better cell survival and the differentiation of Mo into M phi displaying certain morphological differences as compared to control M phi such as an increased expression of Max-1 antigen, CR3 and Fc gamma II receptors, higher phagocytic properties and increased capacities of cytotoxicity and TNF secretion when the cells are further activated by IFN-gamma. Furthermore, GM-CSF treated cells exhibit a low-grade proliferation although the nature of the proliferating cells has not been entirely elucidated. We conclude that the GM-CSF treated M phi would be particularly suitable for adoptive immunotherapy.

Antibodies, Monoclonal↗
PubMed1991

Sequence of the iaa and ipt region of different Agrobacterium tumefaciens biotype III octopine strains: reconstruction of octopine Ti plasmid evolution.

The TA regions of biotype III octopine/cucumopine (OC) Ti plasmids are closely related to the TL region of the biotype I octopine Ti plasmids pTiAch5 and pTi15955. Sequence analysis shows that the limited and wide host range biotype III OC TA regions are derived from a common ancestor structure which lacked the 6a gene found in the biotype I octopine TL region. The TA region of the wide host range OC Ti plasmids has conserved most of the original TL-like structure. In most wide host range OC isolates the TA-iaaH gene is inactivated by the insertion of an IS866 element. However, the TA region of the wide host range isolate Hm1 carries an intact TA-iaaH gene. This gene encodes a biologically active product, as shown by root induction tests and indole-3-acetic acid measurements. The limited host range OC Ti plasmids pTiAB3 and pTiAg57 have shorter TA regions which are derived from a wide host range TA region. The AB3 type arose by an IS868-mediated, internal TA region deletion which removed the iaa genes and part of the ipt gene and left a copy of IS868 at the position of the deleted fragment. The pTiAB3 iaa/ipt deletion was followed by insertion of a second IS element, IS869, immediately 3' of the ipt gene. pTiAg57 underwent the same iaa-ipt deletion as pTiAB3, but lacks the IS868 and IS869 elements. Analysis of the various TA region structures provides a detailed insight into the evolution of the biotype III OC strains.

Amino Acid Sequence↗
PubMed1991

Effects of oxygen free radicals on articular chondrocytes in culture: c-myc and c-Ha-ras messenger RNAs and proliferation kinetics.

Since oxygen free radicals are believed to play an important role in cartilage degradation, we studied the effects of these radicals generated by the hypoxanthine xanthine oxidase system on rabbit articular chondrocytes in culture. Among the damages induced by these radicals, cell proliferation inhibition and G2 arrest were observed. To elucidate the mechanisms involved in this phenomenon, the expression of c-myc and c-Ha-ras genes whose products are associated with cell growth control was studied. Results showed that in chondrocytes, c-myc and c-Ha-ras expression was particularly important during the G1 phase of the cell cycle and that oxygen reactive species, especially H2O2, induced an important decrease of c-myc and c-Ha-ras mRNA levels. Chondrocytes cell cycle analysis revealed an accumulation of cells in G2 phase. It led us to suggest that the chondrocyte cell cycle perturbations observed after oxygen free radicals treatment could be associated with the decrease of c-myc and c-Ha-ras expression.

Animals↗
PubMed1991

Synthesis of complement components C2 and C4 by human monocyte-derived macrophages during in vitro differentiation in serum-free culture conditions.

In order to analyze the kinetics of complement component synthesis by human monocytes/macrophages, we have developed a system of defined culture conditions in the absence of serum. Moreover, the use of the polymerase chain reaction (PCR) provides a high sensitivity for the detection of mRNAs and the study of the regulation of complement component synthesis by these cells. Human blood monocytes were collected and purified by cytapheresis and elutriation, and then cultured in nonadherent cell culture bags for up to 3 weeks. Cells were grown in Iscove's modified Dulbecco's medium supplemented with alpha-phosphatidylcholine, transferrin, insulin, glutamine and antibiotics. The phenotypic and functional properties of macrophages differentiated under these serum-free culture conditions have been previously analyzed [1]. Secretion of complement component was measured by a hemolytic assay. mRNA was prepared using guanidine isothiocyanate extraction followed by cesium gradient ultra-centrifugation. cDNA was obtained by reverse transcription, then amplified by PCR. Fresh monocytes did not display any secretion of C2 as measured by hemolytic assay. However, C2 secretion was detected on and after the 3rd day of serum-free cultured unstimulated monocytes. The rate of C2 production increased along with macrophage differentiation up to the 3rd week of culture. We were not able to detect any functional C4 secretion. In preliminary studies, C2 and C4 mRNAs were detected in macrophages and in unstimulated fresh monocytes. These preliminary studies show that the serum-free culture conditions we have developed allow very satisfactory survival and differentiation of human monocytes, and provide optimal conditions for the study of their secretory activity.

Cell Differentiation↗
PubMed1990

[Association of 5-FU, CDDP and hypofractionated radiotherapy in recurrences of subtentorial astrocytomas and malignant gliomas in adults].

Twenty-seven patients who had a relapse of astrocytomas or supra-tentorial malignant gliomas, previously treated by radio-surgical combination or exclusive irradiation, underwent a combination of 3 courses of 5-FU, cis-platyl and hypofractionated irradiation. No objective response was observed, but there was a progression of the tumor in 33% of the cases, and no change in 67%. Overall median survival was 7 +/- 1.5 months. The 20 patients with grade III or IV astrocytomas had a lower median rate than the 7 patients with grade II astrocytomas or oligodendrogliomas: 6 +/- 1.8 months versus 18 +/- 3.2 (P = 0.16). Median survival was 14 +/- 2.7 months for neurological responders and 6 +/- 2.1 months for non-responders (P = 0.017).

Adult↗
PubMed1989

Effects of oxygen-free radicals on proliferation kinetics of cultured rabbit articular chondrocytes.

It can be postulated that among the factors implicated in cartilaginous lesions, oxygen-derived free radicals seem to have a prominent part. To investigate this hypothesis, rabbit articular chondrocyte cultures have been exposed to oxygen-derived reactive species generated by the hypoxanthine-xanthine oxydase system. We observed a dose-dependent decrease of cellular growth. In order to explain this result, cell cycle progression and binucleate cell fractions have been studied. A greater number of binucleate cells and an increase in cell volume were observed. Flow cytometry analysis revealed a perturbation in cell cycle progression leading to a significant increase in the proportion of cells in G2 phase and an important augmentation in cell protein content confirmed by biochemical assays. This model shows which type of alteration can be induced by oxygen-derived free radicals in vitro. In addition, we deem this model to be useful for studying degenerative processes and for screening drugs that can scavenge oxygen-free radicals.

Animals↗
PubMed1989

Sequence and distribution of IS866, a novel T region-associated insertion sequence from Agrobacterium tumefaciens.

We have identified a new insertion sequence, IS866, located in the auxin synthesis gene TA iaaH of Tm4, a wide host range biotype III octopine/cucumopine type Agrobacterium tumefaciens strain with two T regions on its tumor-inducing (Ti) plasmid, TA, and TB. IS866 is 2716 bp long, has inverted repeats of 27 bp with three mismatches, and generates 8-bp direct repeats upon integration. In addition to IS866, pTiTm4 carries two copies of a related element, IS867, associated with TA and TB, respectively. A systematic study of 92 virulent Agrobacterium strains has shown that among the three biotypes all octopine/cucumopine and vitopine biotype III isolates contain IS866-like elements. The various octopine/cucumopine Ti plasmids always carry IS866 and IS867 at the same position as in pTiTm4. The chromosomes of the bacteria which contain these Ti plasmids also carry IS866 and IS867 copies but in varying numbers and locations.

Bacterial Typing Techniques↗
PubMed1989

Sequential combination of 5-fluorouracil, cis-platinum and irradiation in unresectable non-small cell lung cancer.

Twenty patients with unresectable non-small cell lung carcinoma, 15 stage III and 5 stage IV (supraclavicular lymphadenopathy) were treated with a combination of three courses of chemotherapy and hypofractionated irradiation followed after 3 weeks by split-course radiotherapy. Each course was repeated every 3 weeks with the following sequence. Cis-platin (CDDP) (20 mg/m2) was given in a 20-min infusion, followed by a 2-h infusion of 5-fluorouracil (5-FU) (400 mg/m2) on days 1, 2, 5 and 6. Radiation with a dose of 3 Gy on the target volume was given on days 3 and 4, after a 2-h infusion of 5-FU (400 mg/m2). Split course of irradiation consisted of 16 Gy in 5 fractions repeated after 3 weeks interval. The objective response rate was 75%. Median follow-up was 24 months, the median survival was 14 months. The 1-year survival was 53% and the 2-year survival was 16%.

Actuarial Analysis↗
PubMed1989

Plasma cell panniculitis: a unique clinical and pathologic presentation of linear scleroderma.

A 64-year-old woman had an 11-month history of a highly inflamed linear eruption that affected the left arm, including the dorsal aspect of the hand. It was characterized histologically by an intense plasma cell infiltrate extending throughout the dermis and subcutaneous fat. During the subsequent 2 years, the area evolved into a linear sclerotic plaque in keeping with the diagnosis of linear scleroderma. This case represents a clinical and pathologic presentation of linear scleroderma not previously emphasized in the literature.

Age Factors↗
PubMed1989

[A proposed prototype for recording and analysis of mandibular movement: the Cinétic].

The investigation of means of recording mandibular movement has aroused the interest of a considerable number of researchers. Their own devices, increasingly ingenious, all display certain advantages and shortcomings. The need for a device more appropriate to the needs of day-to-day odontological use has been felt for some time. By giving a broad explanation of how it works, we have tried to assess the possibilities of the proposed prototype, the Cinetic. It measures movement of the dentalium in all three dimensions simultaneously. Since its reliability, when tested by a study concerning a sample of 40 patients, proved entirely satisfactory, a more sophisticated version was promptly devised. This latest Cinetic allows the ROZENCWEIG dyskinesia index, to be calculated, the FARRAR diagram to be drawn, and the mastication movements to be analysed by giving a visual display of the mandibular opening and closing trajectories, the speed diagram, the duration of the cycle, mandibular velocity and acceleration, and a breakdown of the cycles for each respective side. In order to be fully competitive, the Cinetic lacks the capacity to record and analyse condylar movement. Work on incorporating these features is currently at an experimental stage.

Dental Equipment↗
PubMed1988

[Comparative study of 3 methods of evaluation of antiseptic products and disinfectants in quality control].

For choosing a protocol of determination of bactericidal activity of antiseptic and disinfectant products, we have compared a method using an MS2 Abbott system and the classic methods: membrane filtration and dilution-method by transfer loops. The bactericidal-activity of 12 antiseptic solutions are determined. The results shown that there was no significative difference between the automated system and AFNOR specifications. The dilution-method by transfer loops gave higher bactericidal concentrations than the two other methods.

Anti-Infective Agents, Local↗
PubMed1988

Adult phyllostomid (bat) enamel by scanning electron microscopy--with a note on dermopteran enamel.

This study assesses the enamel of five phyllostomids of differing feeding habits; only one example of the microchiropteran super-family Phyllostomoidae having previously been studied by SEM. A dermopteran was also examined to ascertain whether the enamel might reveal insectivore, chiropteran or primate characteristics. The five phyllostomids were found to display the additional crystallite discontinuity feature (minor boundary plane or seam) which is a major characteristic of all the bats we have so far examined - with the exception of two megachiropterans. The enamel of the four fruit and nectar feeders (Phyllostomus, Carollia, Glossophaga and Artibeus) is essentially similar and different to that of the blood feeder (Desmodus). The differentiating factor for the two groups is the poor degree of prism development in Desmodus; the prisms being restricted to the inner two thirds of the enamel over the cusps or sectorial ridge, and lacking in the greater part of the axial and the sulcular enamel. The poor prism development in the vampire bat raises interesting questions from both an ontological and a phylogenetic point of view. The dermopteran (Cynocephalus sp.) displays horse-shoe shaped prisms with associated minor boundary planes (seams); an appearance entirely similar to those microchiroptera we have examined. This finding could be advanced as evidence for a close phylogenetic relationship between the Dermoptera and Chiroptera as these features are not found to the same extent in insectivores or in primates; the other two orders to which dermopterans are assigned. The evolutionary significance of the seam feature is being studied further; it is very likely to be of importance in unravelling the history of mammalian enamel.

Animals↗
PubMed1987

Susceptibility of Torulopsis glabrata in the presence of six antifungal agents determined by comparison of growth at several pHs.

We describe a method using an automated system whereby fungistatic activities can be determined in several conditions. The process was adapted to Torulopsis glabrata, and it showed that benzalkonium chloride, chlorhexidine gluconate, and thimerosal preserve fungistatic activities in acidic medium, whereas acidification reduces the activity of povidone iodine and poloxamer.

Antifungal Agents↗
PubMed1987

[Use of the MS2 automated system in the determination of the activity of 5 antiseptic drugs: quality control].

The study of growth curves of Klebsiella pneumoniae and Staphylococcus aureus in presence of five antiseptics, established using a MS2 Abbott system is presented. From our results, the advantages of automation after the adaptation of the method for the determination of bactericidal properties are examined. This technique may be proposed for the quality control of such drugs.

Anti-Infective Agents, Local↗