Biomedical subjects

L Bordenave

Publications and source records attributed to L Bordenave.

At least 19 recordsLinked to original sources

PubMed2006

Effect of laser modified surface microtopochemistry on endothelial cell growth.

The introduction of microelectronics technology in the area of biological sciences has brought forth previously unforeseeable applications such as DNA or protein biochips, miniaturized, multiparametric biosensors for high performance multianalyte assays, DNA sequencing, biocomputers, and substrates for controlled cell growth (i.e. tissue engineering). We developed and investigated a new method using "cold" excimer laser beam technology combined with microlithographical techniques to create surfaces with well defined 3D microdomains in order to delineate critical microscopic surface features governing cell-material interactions. Microfabricated surfaces with microgrooves 30-3 microm deep, 10 - 1 microm wide spaced 30 microm apart were obtained with micron resolution, by "microsculpturing" polymer model surfaces using a computer controlled laser KrF excimer beam coupled with a microlithographic projection technique. The laser beam after exiting a mask was focused onto the polymer target surface via an optical setup allowing for a 10-fold reduction of the mask pattern. Various 3D micropatterned features were obtained at the micron level. Reproducible submicron features could also be obtained using this method. Subsequently, model human umbilical endothelial cells (HUVEC) were cultured on the laser microfabricated surfaces in order to study the effects of specific microscopic surface features on cell deposition and orientation. Cell deposition patterns were found to be microstructure dependant, and showed cell orientation dependency for features in the cell range dimension, a behaviour significantly different from that of a previously studied cell model (osteoprogenitor cell). This model may be a promising in so far as it is very rapid (a time frame less than a second per square centimeter of micropatterned surface) and provides further insights into the effects of surface microtopography on cell response with possible applications in the field of biosensors, biomedical and/or pharmaceutical engineering sciences.

Cell Culture Techniques↗

PubMed2006

Functionalization of biomaterials and cell to cell communication.

In the field of osseous substitution, the possibilities being offered to the surgeons prove sometimes difficult to apply in particular in the case of great losses of osseous substance. For these reasons, it is necessary to develop innovative techniques to satisfy the request increasing for substitutes and to see appearing on the market solutions combining availability, perenniality and biosecurity of the implants. The implantation of stem cells in a biomaterial opens a way of development of therapeutic substitute. Moreover, in order to optimize the rehabitation of the biomaterials by the cells and the host tissues, the second approach consists in modifying the surface of materials by the coating or the grafting of adhesive factors in order to stimulate their colonization. At least, one cannot consider a tissue mechanism of repair without a better knowledge of the respective role of the various cell populations implied in the rebuilding of this tissue and their cell to cell communication processes.

Alloys↗

PubMed2005

In vitro endothelial cell susceptibility to xenobiotics: comparison of three cell types.

In three different endothelial cell (EC) cultures (primary human umbilical cord vein, so-called HUVEC; and immortalized cell lines HBMEC and EA-hy-926), the effects of different xenobiotics were studied in order to standardize vascular EC models for in vitro pharmacotoxicological studies. Cell characteristics were first investigated by the production and the mRNA levels of known endothelial markers in the three EC culture models. EC secretory products, tissue plasminogen activator (tPA) and von Willebrand factor (vWF), were present in the supernatant of the immortalized cell lines. The mRNA levels of vWF, tPA, platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31), and beta -integrin subunit, which are involved in the control of platelet function, coagulation, and fibrinolysis as well as in cell-matrix interactions, were investigated in all EC types. For at least three parameters, cultured cells provided marked characteristics of EC phenotype, in HUVEC and in immortalized cell lines, regardless of their origin from the macro- or microcirculation. Toxicity experiments were assessed after 24 h exposure to cadmium, cyclosporin A and cisplatin by MTT assay. These experiments show nonsignificant difference in susceptibility to cyclosporin A and cadmium on HUVEC, HBMEC, and EA-hy-926. However, HBMEC, seems to be highly susceptible to cisplatin compared to HUVEC, the latter being more sensitive than EA-hy-926. For experiments conducted with cyclosporin and cadmium, cell lines could constitute an alternative material for routine cytotoxicity studies.

Biomarkers↗

PubMed2005

In vitro endothelialized ePTFE prostheses: clinical update 20 years after the first realization.

The replacement of arteries with synthetic vascular prostheses often leads to failure when small-diameter or low-flow locations are concerned, due in part to the thrombogenicity of the graft surface. In order to improve long-term patency of these grafts, the concept of endothelial cell seeding has been suggested, the composite structure resulting from the combination of biologically active cells to prosthetic materials thus creating more biocompatible vascular substitutes. To achieve endothelialization of synthetic grafts, previous efforts aimed at "one-stage" procedure in the 1980's seemed clinically feasible but results of reported clinical trials were controversial and mostly disappointing. An alternative method is an in vitro complete and preformed endothelial lining at the time of implantation: the "two-stage" procedure which implies harvest and culture of autologous endothelial cells. Up to date, the latter approach demonstrated its superiority in terms of significantly increased patency of the grafts that underwent endothelialization several years earlier.

Blood Vessel Prosthesis↗

PubMed2004

Changes in type B natriuretic peptide (BNP) concentrations during cardiac valve replacement.

OBJECTIVE: The aim of our study was to investigate the ability of BNP levels to reveal the immediate post-surgery cardiac function improvement. We measured the perioperative variations in BNP concentrations in patients scheduled for cardiac surgery with cardiopulmonary bypass (CPB), chronic mitral regurgitation, valvular aortic stenosis, or myocardial ischaemia. METHODS: Three groups were included: patients with coronary artery bypass graft (CABG, group I, n = 14), aortic (AVR, group II, n = 14) or mitral (MVR, group III, n = 7) valve replacement. BNP assay was performed at the induction of anesthesia, immediately after the CPB, at the arrival in the intensive care unit, 4 h, 8 h and 12 h after the arrival in ICU. RESULTS AND CONCLUSION: The occurring variation in BNP levels after the operation is an increase whatever the corrective surgery, underlying the relative lack of specificity of BNP with regard to the cardiac pathology. Besides iatrogenic cardioplegia one can supposes that cardiac surgery involves other major stimuli such as anesthesia, sternotomia, hemodynamics, post-operative that could influence in a non specific way BNP levels.

Aged↗

PubMed2004

[Pollen content of the Paris air: comparison of the results obtained by two samplers for the year 2003].

During the 2003 season, a second pollen collector has been established in Paris city (Audubon site) to study the representativeness of the initial collector situated on the roof of the Pasteur Institute. The Hygiene Laboratory of Paris followed the pollen counts from the two collectors, during the period going from May to September. Both the samplers are Lanzoni model with a flow rate of 10 l x min(-1). The quantitative results show that no statistical difference exists between the pollen counts obtained from the 2 sites (Mann-Withney test, p > .05). The dominant species are Urticaceae, Poacae and Castenea species for the 2 collectors. Their counts are similar except for Poacae whose results are higher at the Audubon site. The collection period do not take into account the pollen production period of many trees species because of the late installation of the collector on the Audubon site. The results show that the two sites chosen for the study of pollen distribution are comparable. Nevertheless, the comparative study should be maintained on the next year to get more details about the observed differences and to collect the early trees pollen.

Air↗

PubMed2003

Caution regarding the combined effects of extracellular matrices and nutrient media on cultured endothelial cells.

To study the influence of smooth muscle cells (SMC) on endothelial cells (EC), different co-culture designs are available, including EC seeding on SMC extracellular matrix (ECM). We explored human umbilical vein endothelial cell (HUVEC) adhesion and proliferation on either in situ or coated ECM, elaborated by HUVECs or human arterial smooth muscle cells (HUASMCs), in the presence of different nutrient media containing varying amounts of fetal calf serum. Coating wells with HUVEC or HUASMC ECMs did not improve HUVEC adhesion 1 h after cell seeding, compared with uncoated wells. HUVEC adhesion on in situ HUVEC-ECM and HUASMC-ECM was significantly increased compared with uncoated wells. The substratum upon which cells are maintained was found to play a crucial role, in conjunction with the medium to which HUVECs are exposed for their proliferative response. These results stress the importance of selecting media in relation to the particular substratum, in order to avoid misinterpretation of data.

Cell Adhesion↗

PubMed2003

[Environmental audits in Ile-de-France].

Mould exposure in indoor environments can cause various health effects: infections, allergies, toxic effects and irritations. We have lead environmental audits (n = 32), at physician's request, in suspected mould allergic patient homes. A deep home visit allows the detection of potential indoor fungal and humidity sources, afterwards, a sample strategy is determinate. Results show that indoor airborne spores concentrations vary from some units (CFU) to more than thousands per m3. In dust samples, the number of spores per gram ranges from hundred to millions. A statistical analysis shows that "mouldy dwellings" are more contaminated than "non mouldy" ones and than outdoor air. Mould species relative presence is specific in each contaminated home, depending on various factors (mouldy support nature, competition between species...).

Air↗

PubMed2002

Development and transferability of apricot and grape EST microsatellite markers across taxa.

EST microsatellite markers were developed in apricot (Prunus armeniaca L.) and grape (Vitis vinifera L.). cDNA libraries from either apricot leaves or grape roots were used in an enrichment procedure for GA and CA repeats. The transferability of EST simple sequence repeat (SSR) markers from apricot and grapevine to other related and unrelated species was examined. Overall, grape primers amplified products in most of the Vitaceae accessions while the apricot primers amplified polymorphic alleles only in closely related species of the Rosaceae. In this taxonomic family, ten EST SSR loci were tested, and one single primer pair, PacB22, was amplified across species and sections in the Prunoideae and Maloideae. Sequencing of EST SSR loci in other species and genera confirmed a higher level of conservation in the microsatellite motif and flanking regions in the Vitaceae compared to the Rosaceae. Two distinct fragments of the PacB22 locus amplified across the Malus and Pyrus genera; however, while the coding region was highly conserved, the microsatellite repeat motif was no longer present. The banding pattern was explained by base substitution and insertion/deletion events in the intronic region of PacB22. This study includes the determination of the degree of polymorphism detected among species and genera in two unrelated taxonomic families and the evaluation of the information provided by the microsatellite repeats and the flanking regions.

Base Sequence↗

PubMed2002

Effect of HUVEC on human osteoprogenitor cell differentiation needs heterotypic gap junction communication.

Bone development and remodeling depend on complex interactions between bone-forming osteoblasts and other cells present within the bone microenvironment, particularly vascular endothelial cells that may be pivotal members of a complex interactive communication network in bone. Our aim was to investigate the interaction between human umbilical vein endothelial cells (HUVEC) and human bone marrow stromal cells (HBMSC). Cell differentiation analysis performed with different cell culture models revealed that alkaline phosphatase activity and type I collagen synthesis were increased only by the direct contact of HUVEC with HBMSC. This "juxtacrine signaling" could involve a number of different heterotypic connexions that require adhesion molecules or gap junctions. A dye coupling assay with Lucifer yellow demonstrated a functional coupling between HUVEC and HBMSC. Immunocytochemistry revealed that connexin43 (Cx43), a specific gap junction protein, is expressed not only in HBMSC but also in the endothelial cell network and that these two cell types can communicate via a gap junctional channel constituted at least by Cx43. Moreover, functional inhibition of the gap junction by 18alpha-glycyrrhetinic acid treatment or inhibition of Cx43 synthesis with oligodeoxyribonucleotide antisense decreased the effect of HUVEC cocultures on HBMSC differentiation. This stimulation could be mediated by the intercellular diffusion of signaling molecules that permeate the junctional channel.

Bone Marrow Cells↗

PubMed2001

Metabolic differences between attached and free-living marine bacteria: inadequacy of liquid cultures for describing in situ bacterial activity.

Marinobacter sp. strain CAB was cultivated with or without porous glass beads as solid support. Two substrates were used: the hydrophilic sodium lactate and a hydrophobic C(18)-isoprenoid ketone (6,10,14-trimethylpentadecan-2-one (TMP)). The substrate adsorption onto the beads was measured. Bacterial adhesion was determined by a direct count technique and amounted to 70% of total cells. In the immobilised cell cultures (ICC), generation times were 1.5 and 1.8 times shorter than in the planktonic cultures (FCC) with sodium lactate and with TMP, respectively. In ICC, the growth yields were lower (15.3(FCC) x 10(9) and 0.8(ICC) x 10(9) bacteria mg(-1) of sodium lactate; 50(FCC) x 10(9) and 35(ICC) x 10(9) bacteria mg(-1) of TMP). The mineralisation of substrates was estimated after mass spectrometric determination of the CO2 production rates of both free and immobilised cell cultures. The results indicated a higher specific CO2 production rate in the ICC with sodium lactate (3.1(FCC)+/-0.2 and 3.5(ICC)+/-0.3 nmol CO2 mg(-1) protein min(-1)) but not in the ICC with TMP (1.9(FCC)+/-0.7 and 0.5(ICC)+/-0.3 nmol CO2 mg(-1) protein min(-1)). The affinities for the two substrates were lower in the presence of the solid support (K(m,ICC)=18.2+/-0.2 microM and 37.1+/-2.0 microM, for sodium lactate and TMP, respectively) than without support (K(m,FCC)=8.5+/-1.5 microM and 8.4+/-1.2 microM, for sodium lactate and TMP, respectively). Moreover, the presence of a solid support showed a lower inhibition by the TMP (K(i,FCC)=3.8+/-1.0 microM and K(i,ICC)=12.2+/-2.5 microM) which may explain why the immobilised cell cultures degraded hydrophobic TMP more efficiently than the planktonic cultures.

Bacterial Adhesion↗

PubMed2001

Assessment of brain natriuretic peptide in patients with suspected heart failure: comparison with radionuclide ventriculography data.

BACKGROUND: The aim of the study was to prospectively evaluate patients with suspected or known heart disease using plasma brain natriuretic peptide (BNP) measurement and radionuclide ventriculography to examine whether left ventricular dysfunction is associated with an abnormal rise of BNP concentration. METHODS: Patients (n=153) and controls (n=14) underwent radionuclide ventriculography to determine Left ventricular Ejection Fraction (LVEF) and measurement of plasma BNP concentration using a commercial kit. RESULTS: Plasma BNP concentration in controls was significantly lower than that in patients whatever the stage of the disease, significantly lower than that of patients with normal LVEF (LVEF>55%); than that of patients with altered LVEF (LVEF< or =40%); and than that of patients with moderately reduced LVEF (40%<LVEF< or =5%). Comparisons between groups of patients showed that the more severe the disease, the higher the BNP level. From the ROC curve, a plasma BNP concentration of 52 pg/ml was attached to a 85% sensitivity and 82% specificity in identifying patients with LVEF< or =40%. CONCLUSIONS: Plasma BNP concentration provides a reliable and sensitive marker of LV systolic dysfunction evaluated by a nuclear medicine technique, and could be a potential screening test to identify patients for additional investigations.

Cardiac Output, Low↗

PubMed2001

Evaluation of an in vitro endothelialized vascular graft under pulsatile shear stress with a novel radiolabeling procedure.

OBJECTIVE: To improve the hemocompatibility of vascular grafts, endothelial cell (EC) seeding of biomaterials prior to implantation is critical. The current in vitro study was designed to investigate such a feasibility on a collagen-coated heparin-bonded graft and to evaluate cell detachment upon pulsatile shear stress. MATERIALS AND METHODS: Endothelial cells (EA-hy-926) were seeded onto grafts. The endothelialization of the grafts was evaluated by the [3H]-thymidine incorporation, scanning electron microscopy (SEM) and histological examinations. After in situ EC radiolabeling with a novel 99mTc technique, the prostheses were exposed to pulsatile shear stress (0.27 N/m2), mimicking the shear rate occurring in a superficial femoral artery, for 3 h in a flow circuit and EC loss quantified by gamma camera detection. RESULTS: Complete EC coverage was achieved after 5 days. Three hours of artificial perfusion resulted in a low EC loss (12.9+/-0.8%, n = 7). SEM shows EC withstanding shear stress in valleys of prosthesis circumvolutions. CONCLUSIONS: These satisfactory results could be explained by the high affinity of EC for heparinized surfaces in addition to cell surface receptors involved in adhesion to collagen.

Autoradiography↗

PubMed2000

Effect of human endothelial cells on human bone marrow stromal cell phenotype: role of VEGF?

Angiogenesis is a tightly regulated process involved in growth, repair, and bone remodeling. Several studies have shown that there is a reciprocal regulation and functional relationship between endothelial cells and osteoblast-like cells during osteogenesis, where systemic hormones and paracrine growth factors play an active role. Angiogenesis is induced by a variety of growth factors; among them vascular endothelial growth factor (VEGF) may be an important mediator for the angiogenic process involved in bone physiology. We studied the VEGF effect on osteoblast progenitor cells (Human Bone Marrow Stromal Cells: HBMSE) cultured alone or associated with endothelial cells (Human Umbilical Vein Endothelial Cells: HUVEC) in different co-culture models (co-culture with or without direct contact, conditioned medium), to determine the influence of VEGF on these cells and on their relationship. In agreement with other studies, we show that HBMSC express and synthesize VEGF, HUVEC conditioned medium has a proliferative effect on them, and early osteoblastic marker (Alkaline phosphatase activity) levels increase when these cells are co-cultured with HUVEC only in direct contact. However, unlike previous studies, we did not find that VEGF increased these processes. These results suggest that the intercommunication between endothelial cells and osteoblastic-like cells requires not only diffusible factors, but also involving cell membrane proteins.

Alkaline Phosphatase↗

PubMed2000

Cultured differentiated human urothelial cells in the biomaterials field.

To review the use of normal cultured differentiated human urothelial cells in the biomaterials field, we checked the literature for human urothelial cells in culture (HUC) both for their use in biocompatibility assessment and as bioartificial devices. The in vitro culture of differentiated human urothelium is now a simple and reliable procedure. These techniques provide new tools for biocompatibility assessment of urinary biomaterials, because for the rational design of a testing procedure, it is preferable that the particular cell culture models selected should be closely related to the end-use application. The emerging use of HUC culture should lead to the development of bioartificial tissue for urinary tract reconstruction. Tissue engineering techniques require urothelial cells and cell delivery matrices. The cytocompatibility of novel artificial delivery matrices should be assessed in vitro before implantation using cultured HUC to find the best material available.

Biocompatible Materials↗

PubMed2000

Cytotoxicity assessment of latex urinary catheters on cultured human urothelial cells.

PURPOSE: To study the toxicity of latex urinary catheters on cultured human urothelial cells (HUC). MATERIALS AND METHODS: We exposed monolayers of HUC (well characterized for their proliferation, qualitative evaluation and quantitative measurement of cytokeratins) to either pure or diluted liquid latex extracts, obtained under standard conditions or by direct contact with materials. RESULTS: The latex urinary catheter appears to be highly toxic since cell viability and metabolic activity were about 10% of those of negative controls for original extracts. Concerning direct contact, latex reduced cell viability, metabolic activity and cell proliferation of HUC on days 1, 3 and 8. CONCLUSION: The high toxicity of latex on HUC is confirmed for extracts and direct contact. Therefore, it should no longer be used for urinary catheters.

Cells, Cultured↗

PubMed2000

Stability of brain natriuretic peptide (BNP) in human whole blood and plasma.

Brain natriuretic peptide is proposed as a biochemical marker which could provide a useful screening test to select patients for further cardiac investigations in heart failure. The applicability of such a biochemical test in clinics, hospital wards, and clinical laboratories is dependent on its ease of use and on the complexity of sample handling. The present study was undertaken to evaluate the stability of brain natriuretic peptide under a number of different handling conditions (sample collection, storage temperatures, freezing temperatures) assayed with a commercially available kit. The results clearly demonstrate that brain natriuretic peptide is stable at room temperature for 24 hours, or in up to 30 degrees C for 12 hours in the presence and absence of aprotinin, on the condition that brain natriuretic peptide is assayed within one month (frozen at -20 degrees C) after blood collection. The presence of aprotinin prevents brain natriuretic peptide degradation in samples preserved for more than 1 month at -20 degrees C before assay.

Adult↗

PubMed2000

Analytical and prospective evaluation of urinary cytokeratin 19 fragment in bladder cancer.

PURPOSE: We evaluated CYFRA 21-1, an immunoradiometric assay, developed to detect soluble cytokaratin 19 fragment, for its diagnostic performance in bladder transitional cell carcinoma as well as its analytical performance. MATERIALS AND METHODS: We assessed CYFRA 21-1 in the serum and urine of 182 patients, including 66 with bladder transitional cell carcinoma (group 1), 66 with another urological pathology (group 2) and 50 free of urothelial disease (group 3). The power of urinary CYFRA as a diagnostic test for bladder transitional cell carcinoma was evaluated by receiver operating characteristics curve analysis. Analytical performance was assessed by determining intra-assay and interassay precision, and accuracy by dilution testing and recovery of supplemented analyte. RESULTS: Mean urinary CYFRA plus or minus standard deviation was 154.39+/-49.00, 22.6+/-8.9 and 2.40+/-0.14 ng./ml. in groups 1 to 3, respectively (significantly different). Receiver operating characteristics curve analysis revealed optimal 96.9% sensitivity and 67.2% specificity for a threshold value of 4 ng./ml. Analytical determination showed that intra-assay and interassay precision provides a satisfactory coefficient of variation. The assay for accuracy had acceptable recovery in diluted samples as well as in those with supplemented analyte. CONCLUSIONS: The urinary immunoradiometric CYFRA 21-1 assay performs well analytically. Urinary CYFRA 21-1 is a useful marker for diagnosing transitional cell carcinoma and provides sensitivity in low grade disease.

Aged↗