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Biomedical subjects

C Guillaume

Publications and source records attributed to C Guillaume.

At least 19 recordsLinked to original sources
PubMed2006

Differential distribution of adipokines between serum and synovial fluid in patients with osteoarthritis. Contribution of joint tissues to their articular production.

OBJECTIVE: To analyze the distribution of leptin, adiponectin and resistin between paired serum and synovial fluid (SF) samples of patients with osteoarthritis (OA) and to determine the potential sources of these adipokines in the joint. The active free form of leptin was also examined by evaluating the level of the soluble leptin receptor (sOb-R). METHODS: Levels of adipokines and sOb-R were measured by a sandwich enzyme-linked immunosorbent assay in serum and SF collected from OA patients. The levels of adipokines were also determined in conditioned media from cultured joint tissues (synovium, infrapatellar fat pad, meniscus, osteophyte, cartilage and bone). RESULTS: The adipokines exhibited different patterns of distribution between the joint and the circulating compartment. Serum levels of resistin and adiponectin exceeded those in the paired SF. Conversely, leptin SF concentrations were similar or higher than those measured in serum counterparts. Leptin and adiponectin in SF may derive from each joint tissue examined, whereas resistin was not detected in conditioned media of cultured explants. Synovium and infrapatellar fat pad were the major sources of adipokines, but osteophytes released also large amounts of leptin. The sOb-R deficiency found in SF further increased the difference in the bioactive leptin levels between serum and SF. A gender-specific difference was observed with women exhibiting the highest level of free leptin in the joint. CONCLUSION: These data demonstrated that adipokines serum levels are not predictive values for SF determination. The joint cavity is a special space where each adipokine undergoes specific regulatory pathways, strengthening the hypothesis that adipokines may have local effects in the joint and may account for the high prevalence of OA in women.

Adiponectin↗
PubMed2006

Behavior of human osteoblast-like cells in contact with electrodeposited calcium phosphate coatings.

Calcium-deficient hydroxyapatite (Ca-def-HAP) thin films were elaborated on Ti6Al4V substrates by electrodeposition. The coatings exhibit two different morphologies and crystallinities. Human osteoblast-like cells (MG-63) were cultured on the surfaces of these materials; the cell content and viability were evaluated up to 28 days. The scanning electron microscopy and biological investigations showed cells with a normal morphology, good proliferation, and viability from 7 to 21 days. But after 28 days, the number of live cells decreases in both cases; however, this decrease is less important in the case of calcium phosphate (CaP) coating surface when compared with the control (cell culture plastic). The cells cultured on Ca-def-HAP coating exhibit more cellular extensions and extracellular matrix. RT-PCR for type I collagen, alkaline phosphatase, and osteocalcin studies were also carried out, and was found that the CaP enhances gene expression of ALP and OC and thus the differentiation of osteoblast-like cells. Moreover, this study shows that the difference in the morphology of CaP coatings has no effect on the biocompatibility.

Calcium Phosphates↗
PubMed2005

[Case report: a bacteremic pasteurellosis].

Bacteremic pasteurellosis is an uncommon form of Pasteurella multocida infection, usually involved in local infections. This systemic infection often occurs in immuno-compromised patient such as cirrhotic or alcoholic patients, with a high mortality rate (up to 60%). Septic shock may occur and neurological disorders or coma are frequent. We report such a case. Treatment associated local care, antibiotics (beta-lactam antibiotics plus fluoroquinolone) during 14 days and resuscitation of septic shock. Owing these therapies, septic shock was successfully treated without complications.

Aged↗
PubMed2004

Rennet-induced gelation of calcium and phosphate supplemented skim milk subjected to CO2 treatment.

A Doehlert design was performed to study the effect of calcium and phosphate supplementation at 0 to 25 mmol/kg and 0 to 16 mmol/kg, respectively, on the rennet gelation of reconstituted skim milk subjected to pH-reversible CO(2) acidification. Supplemented reconstituted skim milk samples were acidified to pH 5.80 by the addition of CO(2) under pressure and depressurized under vacuum to restore the initial pH value. The second-order polynomial models satisfactorily predicted the effect of salt addition on the micellar molar Ca:P ratio and the average diameter of the casein micelles, whereas only trends were used in the analysis of the rennet-clotting behavior of salt-supplemented, CO(2)-treated milk. Whether added Ca was the most determinant factor on the micellar molar Ca:P ratio, added Pi (a mixture of Na(2)HPO(4) and NaH(2)PO(4)) was the most determinant factor on the other responses studied, and its effect was most pronounced when Ca was simultaneously added. By comparison with control samples, changes observed in this study were essentially due to salt supplementation and not to the CO(2) treatment. Therefore, this CO(2) treatment could be considered as an entirely reversible treatment rather than only pH-reversible, and predictions might be applied to untreated milk. In the case of Ca-supplemented milk, the micellar molar Ca:P ratio increased, the average micellar diameter decreased, and the rennet-clotting properties were improved, whereas opposite effects were observed upon Pi supplementation. Since modification of the micellar molar ratio is the result of change in the chemical composition of micellar calcium phosphate, the effect of calcium and phosphate supplementation on the rennet clotting of milk was found to be also dependent on the nature of the interaction between caseins and colloidal calcium phosphate.

Animals↗
PubMed2003

Biodistribution study of phosphonolipids: a class of non-viral vectors efficient in mice lung-directed gene transfer.

BACKGROUND: A multitude of cationic lipids have been synthesized since they were first proposed for use in gene therapy. Cationic lipids are able to efficiently transfect cells both in vitro and in vivo. Whereas most research groups have focused their investigations on the toxicity of these molecules, and on the location of expression of the DNA transferred by these vectors, little has been done to determine their biodistribution and elimination pathways. Our group has developed a family of cationic lipids termed phosphonolipids. Following a large in vitro screening experiment, we have selected several molecules for in vivo testing, with some of these phosphonolipids forming lipoplexes efficient in transfecting mouse lungs. It was thus of interest to study their fate after intravenous injection. METHODS: The respective biodistributions of both the GLB43 phosphonolipid and plasmid DNA were investigated and compared with DNA expression sites. Using the optimal conditions determined for phosphonolipids, we followed the gene transfer agent and plasmid DNA distributions versus time by radiolabeling them with (14)C and (32)P, respectively. Otherwise, we performed imaging by radiolabeling plasmid DNA with (99m)Tc. RESULTS: The lipoplexes appear to be directly located in the lung after administration. Secondly, the plasmid is released mainly into the lungs and the phosphonolipid vector is rapidly degraded. The hydrophilic moiety of the phosphonolipid is eliminated in the urine, as is the free plasmid. CONCLUSIONS: This study reveals that there are slight differences in the observed results depending on the technique used to label the DNA; secondly, results show that the residence time of phosphonolipids in the mouse body is related to the DNA binding time.

Animals↗
PubMed2003

Effect of controlled kappa-casein hydrolysis on rheological properties of acid milk gels.

An experimental method based on the controlled chymosin-induced kappa-casein hydrolysis of milk was proposed to modify micellar reactivity. Milk samples with a degree of kappa-casein hydrolysis of 19, 35, and 51% were obtained. The physicochemical properties of partially converted casein micelles were determined. The net negative charge of casein micelles was reduced with increasing degree of kappa-casein hydrolysis and a small but significant decrease in hydrodynamic diameter and micellar hydration were noted. Dynamic low amplitude oscillatory rheology was used to monitor the rheological properties of acid milk gels (GDL) made with partially chymosin-hydrolyzed milks in comparison with those of strictly acid and rennet gels. An increase in the gelation pH value was observed with increasing the degree of kappa-casein hydrolysis. The moduli values (G' and G'') reached 2 h after the point of gel were, for all degrees of hydrolysis tested, significantly higher than those of strictly rennet and acid gels. Comparison of changes in delta G'/delta t with time indicated differences in gel formation that could be related to the increased values of G' obtained for acid gel made with chymosin-treated milk. At a given time after gelation (2 h), increasing the degree of kappa-casein hydrolysis in milk led also to an increase in the loss tangent and the serum holding capacity of acid milk gels suggesting a correlation between these two parameters.

Animals↗
PubMed2003

[Medico-economic evaluation of a care management program for asthmatic patients].

This study aimed at measuring the medico-economic interest of a care management programme established for asthmatic patients in the Amiens region ("Action Asthma Amieris") by using and comparing different evaluation tools. Three tools were used in parallel: 1) a questionnaire for collecting information on healthcare received was completed monthly by 305 patients recruited by 73 physicians between November 1998 and January 1999; 2) data issued by the national insurance fund for the years 1998 and 1999, for those patients included after January 1999; and 3) data on all hospitalisations for 1998 and 1999 in the University Hospital Centre obtained from the French hospital information database (PMSI). Data from the national insurance fund and from the PMSI are essential to evaluate costs, since the patients' statements proved to under-estimate the amount of healthcare administered and received. Following the implementation of this asthma care management programme, an increase of pharmaceutical expenses and a decrease in the number of hospitalisations for asthmatic patients were observed.

Adolescent↗
PubMed2002

Visualization of the transgene distribution according to the administration route allows prediction of the transfection efficacy and validation of the results obtained.

Gene transfer to the lung can be achieved via a systemic, that targets the endothelium, or local, that targets the epithelium, delivery route. In the present study, we followed the distribution of a plasmid after transfection using some of our phosphonolipids, which have previously shown their efficiency in transfecting mouse lungs. The plasmid was radiolabeled and varying combinations of plasmid/phosphonolipid were administered by intravenous injection, or by endotracheal spray. The distribution of radioactive labeling was observed over a time course using a gamma-camera. These images were then correlated with the results for luciferase expression levels in the lungs. In each case, lungs were well targeted. However, whereas an intravenous injection reaches all of the lung immediately, progressive diffusion occurs when the plasmid/phosphonolipid is administered via an aerosol. Elimination of the radioactivity associated with plasmid occurs via the urinary tract after intravenous injections, and via the feces using the aerosol delivery approach. The radioactivity detected in the lungs correlated strongly with transgene expression. Thus, such an imaging technique is a powerful strategy to predict the formulation that will generate the best transfection efficiency. This study reveals that scintigraphic imaging permits both validation of the administration method and the results obtained for each animal, thereby reducing the statistical variability of in vivo experiments.

Aerosols↗
PubMed2002

Effect of salt addition on the micellar composition of milk subjected to pH reversible CO2 acidification.

Response surface methodology was used to investigate the effect of salt supplementation on the micellar composition of reconstituted skim milk subjected to acidification by CO2 pressure to pH 5.8, followed by depressurization under vacuum. Using a Doehlert design, calcium and phosphate were added to skim milk in the range of 0 to 25 mmol/kg and 0 to 16 mmol/kg of milk, respectively, and the pH was adjusted to 6.65 +/- 0.02. After carbonation, the milk sample was depressurized, and the pH returned to its initial value without modification of the ionic strength. Micellar composition was assessed by the concentration of micellar Ca, P, Mg, and protein, and the buffering properties of milk. The second order polynomial models satisfactorily predicted the effect of salt supplementation on the micellar composition (R2adj > 0.75). Added calcium was the most determinant factor, and favored the removal of Ca, P, Mg, and proteins from the soluble phase to the micellar phase when this addition was less than 17.5 mmol/kg of milk. Above this concentration, only the concentration of micellar Ca increased. The buffering response surface showed that the amount of micellar calcium phosphate increased to a maximum upon addition of 17.5 mmol of Ca/kg. By comparison with a control sample (supplemented but untreated skim milk), changes were essentially due to salt supplementation and not to the CO2 treatment. We suggest that Ca formed micellar calcium phosphate when added at a concentration less than 17.5 mmol/kg; whereas above this concentration, Ca bound directly to micellar proteins.

Animals↗
PubMed2001

Aerosolization of cationic lipid-DNA complexes: lipoplex characterization and optimization of aerosol delivery conditions.

This study deals with the development of gene therapy in the treatment of lung diseases. It reports on the use of ultrasonic nebulization to administer plasmid-lipid complexes to the lungs of mice to transfect their epithelial cells. A plasmid complexed to cationic lipids was aerosolized using an ultrasonic nebulizer. We then characterized the lipoplex size and visualized the lipoplex by electron microscopy. Finally, we assessed the in vivo transgene expression in the lungs further to the aerosolization of different lipid-plasmid formulations. The nebulizer-generated particles were small and looked like a string composed of little and more or less cubic units. Transgene expression was detected in the lungs of mice further to a 20-min exposure to aerosol particles produced with the ultrasonic nebulizer. The results obtained with our optimized plasmid-lipid-NaCl formulation suggest that this route can be used to administer an appropriate gene to the airways for the treatment of respiratory disorders.

Administration, Inhalation↗
PubMed2000

Systemic administration of cationic phosphonolipids/DNA complexes and the relationship between formulation and lung transfection efficiency.

Performances of cationic lipid formulations for intravenous gene delivery to mouse lungs have been previously reported. We report in this study that cationic phosphonolipids, when appropriately formulated, can be good synthetic vectors for gene delivery to lung after intravenous administration. One of our reagents, GLB43, was capable of mediating a 500-fold higher expression in the lungs of mice than could be obtained with free pDNA alone (P=0.018). We demonstrate that the most important parameters for cationic phosphonolipid transfection activity after systemic administration are the chemical structure of the cationic phosphonolipid, the lipid to DNA charge ratio and the inclusion of co-lipid in the formulation. We report using a luciferase reporter gene that transfection activity in vivo 24 h after cationic phosphonolipid systemic administration could not be predicted from in vitro analysis. In contrast to in vitro studies, cationic phosphonolipids including the oleyl acyl chains (GLB43) were more effective than its analogue with the myristyl acyl chains (GLB73). Using pathological analysis of animal livers, we demonstrate that the toxicity level was correlated with the lipoplex formulation and the lipid to DNA ratio.

Animals↗
PubMed2000

Cationic phosphonolipids as nonviral vectors: in vitro and in vivo applications.

Since the development of the concept of gene therapy using cationic lipids as nonviral vectors by Felgner's group in 1987, numerous molecules have been synthesized. Such vectors were first proposed to avoid viral vector-induced drawbacks. But, it quickly became clear that a thorough knowledge of their physical and chemical characteristics was fundamental to use them under optima conditions. Over the last years our laboratory has developed a family of cationic lipids called phosphonolipids whose structure is based on that of natural phosphonolipids; compared with other vectors, these compounds had to be well-tolerated by biologic membranes. Some of our synthesized molecules exhibited an interesting potential for gene transfer, both in vitro and in vivo. Structural changes in the different parts (hydrophobic, hydrophilic, and intermediary domains) of these vectors were evaluated in vitro on different cell-lines; these studies led us to select some of these molecules to carry out in vivo tests. So, the plasmid/phosphonolipid complexes were first administered to mice by intratracheal and aerosol routes with a beta-galactosidase plasmid as reporter gene. In a second set of experiments, we explored the possibilities offered by intravenous injection; in these studies, we used a luciferase plasmid as reporter gene because of its high sensibility. These experiments revealed a transgene expression essentially localized in the lungs. In a further study, we compared systemic administration with local ones; we, then, observed that the optimum formulation of a given molecule depended on its route of administration.

Aerosols↗
PubMed2000

Phosphonocationic lipids in protein delivery to mice lungs.

Cationic liposomes constitute one of the main approaches currently investigated to introduce a gene with therapeutic properties into a cell. Another alternative consists in directly introducing the normal protein of concern to, for example, restore the deleted function. We report here on in vitro and in vivo results obtained with GLB73, one of the phosphonolipids investigated as gene transfer agents. In previous studies this cationic lipid had shown its DNA-transfer efficacy in vitro and in vivo. We also confirmed the feasibility of protein/cationic lipid delivery in epithelial cells of mice lungs after intratracheal administration by use of a reporter gene (beta-galactosidase). Two quantitative tests (i.e., a chemiluminescent assay and a flow cytometry assay) were used to determine the amount of beta-galactosidase found in the lungs and the percentage of transfected cells. They showed that 50% of the cells of mice lungs were still positive at day 4 after protein/GLB73 delivery. Immunohistochemistry and electron microscopy studies allowed us to determine the spatial distribution and visualize the penetration of our complex into the lungs.

Animals↗
PubMed2000

Articular diffusion of meloxicam after a single oral dose: relationship to cyclo-oxygenase inhibition in synovial cells.

OBJECTIVE: To investigate the distribution of meloxicam in the human knee joint and to compare it with the inhibition of cyclo-oxygenase (COX) activity in synovial cells. DESIGN: Prospective pharmacokinetic study and in vitro laboratory investigation. PATIENTS AND PARTICIPANTS: 42 male and female patients aged 26 to 85 years hospitalised for rheumatic disease and requiring a diagnostic and/or therapeutic knee puncture. METHODS: After a single oral dose of meloxicam 15mg, synovial fluid and blood samples were collected once per patient at various intervals after administration. Meloxicam concentrations were determined by a validated high performance liquid chromatography assay, protein binding by equilibrium dialysis, and pharmacokinetic parameters were calculated by noncompartmental analysis from the mean drug concentration-time profiles. The inhibitory effect of meloxicam on COX activity was investigated separately in unstimulated or interleukin-1beta-stimulated human synovial cells from osteoarthritic patients. RESULTS: Meloxicam was found in synovial fluid at the earliest sampling time (1 hour). Peak concentrations were reached approximately 6 hours postdose in both plasma (842 microg/L) and synovial fluid (320 microg/L). A plateau was observed after the distribution phase (6 hours), corresponding to a constant ratio of drug concentration between synovial fluid and plasma of about 0.47. This ratio was higher in patients with acute inflammation (0.58) than in those with no inflammation (0.38). Meloxicam was extensively bound to protein, mainly to serum albumin. The area under the drug concentration-time curve (AUC) in plasma was more than 2.5 times that in synovial fluid. The AUC for free meloxicam was similar in plasma and synovial fluid. The 50% inhibitory concentrations (IC50) for basal and stimulated COX activity in human synovial cells were 33.7 nmol/L (11.8 microg/L) and 2.0 nmol/L (0.70 microg/L), respectively. The free concentration of meloxicam in synovial fluid was higher than the IC50 for stimulated COX activity from 6 to 36 hours postdose. CONCLUSION: On the basis of free synovial concentrations and the IC50 for stimulated COX activity, meloxicam is expected to have a long duration of action. Inhibition of COX activity is expected to be more marked in inflamed synovium compared with non-inflamed synovium.

Administration, Oral↗
PubMed1998

New biocompatible cationic amphiphiles derivative from glycine betaine: a novel family of efficient nonviral gene transfer agents.

With the aim of developing new efficient agents for transfecting of eukaryotic cells we have designed and synthesized a novel family of cationic lipid vectors derived from glycine betaine. In this study we present three novel molecules differing by the length of their aliphatic chains (R=12,R=14,R=16). The lyotropic properties of these cationic lipids have been determined, and their transfection efficiency on different cell lines evaluated, using a luminescent assay. Two of these compounds, GB14 and GB12 are efficient in vitro experiments. Cytoxicity evaluation of these new molecules showed promising results with a low cytotoxicity, especially when co-lipids were included in the formulation. These compounds represent a new family of gene transfer vectors which display good transfection efficiency and low toxicity, possibly due to the natural properties of glycine betaine. These compounds have great potential for the future development of in vivo gene transfer protocols.

Betaine↗
PubMed1998

Transgene expression kinetics after transfection with cationic phosphonolipids in hematopoietic non adherent cells.

Cationic lipids are considered to be capable of efficiently and safely mediating DNA transfer into cells, although expression is transient. A new family of cationic lipids, called phosphonolipids, has been developed, with the relationship between the hydrophobic domain of the lipid molecules and the significant enhancement of transduction efficiency in a non-adherent cell line characterised in the present study. The kinetics of transfection efficiency were also investigated. Our results demonstrate that the peak of the transient expression of these reporter genes mediated by cationic lipids occurred within 3 to 14 days, depending on the aliphatic chain length of the complex used and on its formulation in the presence or absence of DOPE. Furthermore, the kinetics of transgene expression were found to differ in adherent and non-adherent cells. These results were obtained using three different techniques: CPRG, luminescence, and FACS-gal, and were in agreement with electron microscopy studies. We thus hypothesized that the plasma membrane composition of cells could affect the efficiency of transfection with cationic lipids. Our results suggest that phosphonolipids constitute a promising class of compounds for gene transfer protocols, and that galenic optimization should improve and modify the transfection efficiency of these DNA-lipid complexes.

Cations↗
PubMed1997

Clinical features and echocardiography of embolism during cemented hip arthroplasty.

PURPOSE: In previous studies the degree of embolization detected by transoesophageal echocardiography (TEE) during cemented total hip arthroplasty (THA) did not correlate with changes in haemodynamic variables nor did it result in persistent ventilation-perfusion mismatching. The aim of this study was to record evidence of embolism and to relate the findings to demographic data and the subsequent clinical course of the patients during THA. METHOD: Forty-eight patients scheduled to undergo elective cemented THA during general anaesthesia were monitored. A TEE probe was inserted with special attention to the right atrium (RA), the right ventricle (RV) Haemodynamic (heart rate, arterial blood pressure, central venous pressure) and blood-gas variables were measured repeatedly during the operative procedure (after induction, placement of the acetabular component, placement of the femoral component, relocation of the hip joint). Grading of venous embolism at these times was based on the size of particles detected by TEE (three-minutes video segments of each periods) and correlated with demographic, haemodynamic and blood-gas data. RESULTS: The TEE monitoring revealed showers of echogenic material traversing the RA and RV in all but one patients during reaming and cementing of the acetabular and femoral components, and during relocation of the hip joint. No correlation was observed between frequency or size of embolic particles and demographic or blood-gas and haemodynamic variables studied at the same times. CONCLUSION: This study failed to show any clinical impact of TEE detected emboli during cemented THA.

Aged↗