PubMed Health⌕ Search

Biomedical subjects

G Faure

Publications and source records attributed to G Faure.

At least 19 recordsLinked to original sources
PubMed2006

Effect of cyclic stretching and foetal bovine serum (FBS) on proliferation and extra cellular matrix synthesis of fibroblast.

It is well known today that mechanical forces are one of the important factors that induce a variety of cellular responses including morphological changes, protein synthesis, and gene expression and which are involve in tissue remodelling. We studied the effect of uniaxial cyclic stretching on the proliferation, collagens, and tenascin C mRNA expression of fibroblasts under different concentrations of foetal bovine serum. Proliferation was studied by cell cycle analysis, mRNA expression of collagen and tenascin C was studied by RT-PCR. Human fibroblasts were grown in silicon sheet coated with 1% gelatin. Cyclic stretching (5% elongation) was applied at 0.5 Hz (30 cycle/min), for 24 h with two concentrations of the serum (0.5%, 10% FBS). We showed that stretching enhances the synthesis of collagen and tenascin C, but do not act on the proliferation. In contrast, higher concentration of serum enhances the proliferation. These findings suggest that both mechanical stretching and serum concentration can modulate proliferation and extra cellular matrix synthesis in human fibroblasts.

Animals↗
PubMed2003

[Anti-ovarian antibodies and in vitro fertilization: cause or consequence?].

OBJECTIVES: To assess anti-ovarian antibodies (AOA) in serum samples at various times of in vitro fertilization (IVF) attempts to determine whether ovarian stimulation could result in the production of such autoantibodies in women. PATIENTS AND METHODS: Prospective study on 134 patients and 138 IVF cycles using a classical long protocol. For each attempt, four serum samples were obtained, respectively, at the onset of downrelation (S1), end of downregulation (S13), after 7 days of follicular stimulation (S21) and the day of follicular puncture (SP). Five hundred and fifty two samples were tested with an enzyme-linked immunosorbent assay for three isotypes (IgG, IgA, IgM) of AOA. RESULTS: In the whole group, mean concentrations of AOA for each isotype were compared group by group: S1-S13, S1-S21, S1-SP, S13-S21, S13-SP, S21-SP. Not any significant difference was observed whatever the isotype considered. DISCUSSION AND CONCLUSION: This study shows the absence of influence of endogenous or exogenous ovarian stimulation by gonadotropins on anti-ovarian autoimmunity.

Adult↗
PubMed2003

[What are the antigenic targets in the ovary?].

The ovary can be the target of an autoimmune disease involving many different autoantigens. The clinical feature of this disease often results in premature ovarian failure or infertility and may be either isolated or associated with other autoimmune pathologies, especially with adrenal autoimmunity. The diagnosis of an autoimmune mechanism relies on the presence of anti-ovarian antibodies, whose prevalence is quite variable according to the different methods used to detect them, and to the different stages of the disease. In addition, their clinical significance is not always clear, as to their pathologic or epiphenomenal nature. However, the study of these autoantibodies has led to the identification of some of their antigenic targets which have to be known for a better understanding of the pathologic mechanisms involved. This paper reviews anti-steroid producing cells, anti-gonadotrophin receptor, anti-gonadotrophin, anti-corpus luteum, anti-zona pellucida and anti-oocyte antibodies.

Autoantigens↗
PubMed2002

The increased histamine release in ischaemic heart disease patients undergoing coronaroangiography is not mediated by specific IgE.

BACKGROUND: The release of histamine by iodinated contrast media (ICM) is higher in coronary artery disease patients than in noncoronary patients during coronary angiogram. METHODS: Eighty-eight patients who underwent a coronary angiography were classified either as having coronary artery disease or as noncoronary patients. Histamine concentration was higher than the 6.8 nM upper limit in 7 cases (group 1), of whom six were coronary artery disease patients. We compared the IgE and complement fractions in plasma of these patients to two control groups with normal histamine blood level, one (group 2) with and the other (group 3) without coronary artery disease. RESULTS: No difference of total IgE and C(3c) and C(4) complement fractions was found among the three groups. Anti-ioxaglate IgE-RIA was positive in only one patient from group 1. The affinity of drug-IgE binding in the serum of this patient was very low (Kd: 18.7 mM). The level of anti-ICM IgE detected by ioxitalamate- and iomeprol-Sepharose RIA was significantly higher in groups 2 and 3 than in group 1. CONCLUSIONS: The higher histamine release in ischaemic heart disease patients undergoing coronaroangiography is not mediated by IgE or complement activation. Further studies are needed to investigate the implication of histamine release factors.

Complement C3c↗
PubMed2001

Assessment by flow cytometry of peripheral blood leukocyte enzymatic activities in HIV patients.

Leukocyte enzymatic activities are important in non-specific protection against bacterial infections, but traditional methods for the detection of intracellular enzymatic activities rely on cumbersome and complex assays. The development of specific substrates, which become fluorescent upon degradation of the biomolecule after its passive entry into intact cells, permits a simplified evaluation of leukocyte enzymatic activities. We have used this method to assess intracellular elastase, collagenase and cathepsin D activities of peripheral blood leukocytes using flow cytometry in a series of HIV patients and healthy controls. Monocytes displayed the highest enzymatic activities for the three proteases tested. In HIV-infected patients, the collagenase and cathepsin D activities of monocytes were significantly lower, whereas the elastase and cathepsin D activities of polymorphonuclear cells were elevated. Slightly higher elastase activity was detected in the lymphocytes of patients. This study demonstrates the feasibility of this new method for the study of intracytoplasmic enzymatic activities. Significant variations were observed in the peripheral blood of HIV-infected patients and different patterns were especially evident in monocytes and polymorphonuclear cells.

CD4 Lymphocyte Count↗
PubMed2001

The major CD9 and CD81 molecular partner. Identification and characterization of the complexes.

By associating with specific partner molecules and with each other, the tetraspanins are thought to assemble multimolecular complexes that may be especially relevant with respect to metastasis. We have previously identified a 135-kDa molecule (CD9P-1) as a major molecular partner of CD9 in cancer cell lines. This molecule was identified, after immunoaffinity purification and mass spectrometry analysis, as the protein encoded by the KIAA1436 gene and the human ortholog of a rat protein known as FPRP. Cross-linking experiments detected a complex of the size of CD9 plus CD9P-1, showing that these glycoproteins directly associate with each other, probably in the absence of any other molecule. The use of chimeric CD9/CD82 molecules revealed the role of the second half of CD9, comprising the large extracellular loop and the fourth transmembrane domain. CD9P-1 was also shown to form separate complexes with CD81 and with an unidentified 175-kDa molecule. It also associated with other tetraspanins under conditions maintaining tetraspanin/tetraspanin interactions. The identification of a protein strongly linked to the tetraspanin web and the production of a specific monoclonal antibody will help to further characterize the role of this "web" under physiological and pathological conditions.

Animals↗
PubMed2001

Increases of IgA milk concentrations correlate with IgA2 increment.

IgA, IgA1, and IgA2 concentrations were determined in 81 defatted human milk samples: colostrum (days 1-5, n = 42), transitional milk (days 6-14, n = 18) and mature milk (days 15-75, n = 21) by immunonephelometry. Correlations were found between total IgA levels and the concentrations of both IgA subclasses (P < 0.0001). The levels of the three molecules decreased over lactation with significant differences (P < 0.05) between colostrum and transitional milk levels and between colostrum and mature milk. Colostral IgA1 and IgA2 mean concentrations dropped respectively from 10.89 +/- 2.12 g/L, and 15.41 +/- 2.10 g/L to 1.83 +/- 0.73 g/L and 3.40 +/- 1.25 g/L in transitional milk reaching finally to 0.36 +/- 0.07 g/L and 0.27 +/- 0.06 g/L in mature milk. IgA2 concentrations were higher than those of IgA1 when the total IgA level was high. The IgA2 levels in colostrum could be an adaptation resistance of IgA to potentially harmful pathogens able to secrete IgA proteases and also a way to regulate colonization of the microflora in the newborn.

Female↗
PubMed2001

Changes in lactoferrin and lysozyme levels in human milk during the first twelve weeks of lactation.

Changes in the lactoferrin and lysozyme concentration of human milk during lactation were determined by microparticle-enhanced nephelometric immunoassays of 360 milk samples collected from 64 lactating volunteers. These 360 samples were colostrum from days 1 to 5 postpartum (142 samples), transitional milk from days 6 to 14 (106 samples), and 112 mature milk samples obtained from days 15 to 28 (34 samples), from days 29 to 56 (50 samples) and from days 57 to 84 postpartum (28 samples). The concentration and percentage of lactoferrin vs. total protein were found to be significantly higher in colostrum (5.8 g/L, 27%) than in transitional milk (3.1 g/L, 22%) or day 15 to 28 mature milk (2.0 g/L, 19%), then increased in day 29 to 56 mature milk (2.2 g/L, 22%) and day 57 to 84 mature milk (3.3 g/L, 30%). The concentration of lysozyme decreased from colostrum (0.37 g/L) to transitional milk (0.27g/L) and day 15 to 28 mature milk (0.24 g/L), then increased in day 29 to 56 mature milk (0.33 g/L) and was highest in day 57 to 84 mature milk (0.89 g/L). The percentage of lysozyme vs. total protein was found to be always rising during lactation: colostrum, 2%; transitional milk, 2%; days 15 to 28, 2%; days 29 to 56, 3%; and days 57 to 84 mature milk, 8%.

Colostrum↗
PubMed2001

Nonenveloped nucleocapsids of hepatitis C virus in the serum of infected patients.

One of the characteristics of hepatitis C virus (HCV) is the high incidence of persistent infection. HCV core protein, in addition to forming the viral nucleocapsid, has multiple regulatory functions in host-cell transcription, apoptosis, cell transformation, and lipid metabolism and may play a role in suppressing host immune response. This protein is thought to be present in the bloodstream of the infected host as the nucleocapsid of infectious, enveloped virions. This study provides evidence that viral particles with the physicochemical, morphological, and antigenic properties of nonenveloped HCV nucleocapsids are present in the plasma of HCV-infected individuals. These particles have a buoyant density of 1.32 to 1.34 g/ml in CsCl, are heterogeneous in size (with predominance of particles 38 to 43 or 54 to 62 nm in diameter on electron microscopy), and express on their surface epitopes located in amino acids 24 to 68 of the core protein. Similar nucleocapsid-like particles are also produced in insect cells infected with recombinant baculovirus bearing cDNA for structural HCV proteins. HCV core particles isolated from plasma were used to generate anti-core monoclonal antibodies (MAbs). These MAbs stained HCV core in the cytoplasm of hepatocytes from experimentally infected chimpanzees in the acute phase of the infection. These chimpanzees had concomitantly HCV core antigen in serum. These findings suggest that overproduction of nonenveloped nucleocapsids and their release into the bloodstream are properties of HCV morphogenesis. The presence of circulating cores in serum and accumulation of the core protein in liver cells during the early phase of infection may contribute to the persistence of HCV and its many immunopathological effects in the infected host.

Amino Acid Sequence↗
PubMed2000

Discriminative immunophenotype of bronchoalveolar lavage CD4 lymphocytes in sarcoidosis.

The diagnosis of pulmonary sarcoidosis relies in part on the observation of alveolar CD4+ lymphocytosis. However, this criterion is not fully discriminative because this anomaly is also found in other types of lung diseases. Among other possible distinctive criteria, we investigated the expression of lymphocyte-addressing molecules, which could differ according to the pathophysiology of lung diseases. We investigated CD103 (alpha(E)beta7 integrin, CD103-beta7), reported to be both expressed on intra-epithelial lymphocytes in mucosal areas, including bronchi, and possibly involved in the recruitment of alveolar lymphocytes. The expression of CD103 was examined on bronchoalveolar lavage lymphocytes from 93 consecutive patients, including 34 patients with CD4+ lymphocytosis. For all patients, the expression of CD19, CD3, CD4, CD8, CD57, LFA1, DR, and CD103 was assessed by flow cytometry. Sarcoidosis seemed remarkably characterized by the lack of CD103 expression on the predominant CD4+ subset. Statistically significant differences were found between patients with sarcoidosis, with other types of CD4+ lymphocytosis, and with other lung disorders in the CD103+ cell levels and in the CD103/CD4 ratio. Combined use of the CD4/CD8 ratio (> 2.5) and the CD103/CD4 ratio (< 0.31) to assess bronchoalveolar lavage lymphocytes is a promising new tool for the diagnosis of sarcoidosis.

Adult↗
PubMed2000

Basic residues of human group IIA phospholipase A2 are important for binding to factor Xa and prothrombinase inhibition comparison with other mammalian secreted phospholipases A2.

Human secreted group IIA phospholipase A2 (hGIIA) was reported to inhibit prothrombinase activity because of binding to factor Xa. This study further shows that hGIIA and its catalytically inactive H48Q mutant prolong the lag time of thrombin generation in human platelet-rich plasma with similar efficiency, indicating that hGIIA exerts an anticoagulant effect independently of phospholipid hydrolysis under ex vivo conditions. Charge reversal of basic residues on the interfacial binding surface (IBS) of hGIIA leads to decreased ability to inhibit prothrombinase activity, which correlates with a reduced affinity for factor Xa, as determined by surface plasmon resonance. Mutation of other surface-exposed basic residues, hydrophobic residues on the IBS, and His48, does not affect the ability of hGIIA to inhibit prothrombinase activity and bind to factor Xa. Other basic, but not neutral or acidic, mammalian secreted phospholipases A2 (sPLA2s) exert a phospholipid-independent inhibitory effect on prothrombinase activity, suggesting that these basic sPLA2s also bind to factor Xa. In conclusion, this study demonstrates that the anticoagulant effect of hGIIA is independent of phospholipid hydrolysis and is based on its interaction with factor Xa, leading to prothrombinase inhibition, even under ex vivo conditions. This study also shows that such an interaction involves basic residues located on the IBS of hGIIA, and suggests that other basic mammalian sPLA2s may also inhibit blood coagulation by a similar mechanism to that described for hGIIA.

Amino Acid Sequence↗
PubMed2000

Interaction of the neurotoxic and nontoxic secretory phospholipases A2 with the crotoxin inhibitor from Crotalus serum.

Crotalus durissus terrificus snakes possess a protein in their blood, named crotoxin inhibitor from Crotalus serum (CICS), which protects them against crotoxin, the main toxin of their venom. CICS neutralizes the lethal potency of crotoxin and inhibits its phospholipase A2 (PLA2) activity. The aim of the present study is to investigate the specificity of CICS towards snake venom neurotoxic PLA2s (beta-neurotoxins) and nontoxic mammalian PLA2s. This investigation shows that CICS does not affect the enzymatic activity of pancreatic and nonpancreatic PLA2s, bee venom PLA2 and Elapidae beta-neurotoxins but strongly inhibits the PLA2 activity of Viperidae beta-neurotoxins. Surface plasmon resonance and PAGE studies further demonstrated that CICS makes complexes with monomeric and multimeric Viperidae beta-neurotoxins but does not interact with nontoxic PLA2s. In the case of dimeric beta-neurotoxins from Viperidae venoms (crotoxin, Mojave toxin and CbICbII), which are made by the noncovalent association of a PLA2 with a nonenzymatic subunit, CICS does not react with the noncatalytic subunit, instead it binds tightly to the PLA2 subunit and induces the dissociation of the heterocomplex. In vitro assays performed with Torpedo synaptosomes showed a protective action of CICS against Viperidae beta-neurotoxins but not against other PLA2 neurotoxins, on primary and evoked liberation of acetylcholine. In conclusion, CICS is a specific PLA2 inhibitor of the beta-neurotoxins from the Viperidae family.

Acetylcholine↗
PubMed2000

[Polyclonal T lymphocyte proliferation in drug lymphocyte activation test].

BACKGROUND: We examined the clonality of the specific T cell reaction activated with specific drug antigens in patients with a positive lymphocyte activation test. PATIENTS AND METHODS: Ten patients were investigated. Their clinical features suggested drug allergy. Six weeks after a skin reaction, skin tests and lymphocyte activation tests were run. For each lymphocyte activation test, we explored the clonality of the T cell proliferation by examining the VJ rearrangement of the TCR gamma locus using polymerase chain reaction and denaturing gradient gel electrophoresis. RESULTS: All samples gave positive lymphocyte activation tests proving in vitro polyclonal T cell proliferation in reaction to a drug. There was no difference in clonality between the pilot lymphocyte activation test and the lymphocyte activation test after stimulation with phytohemagglutinin or with the drug antigen. DISCUSSION: Our findings show that in vitro T cell proliferation induced by a specific drug antigen as disclosed by the lymphocyte activation test is a polyclonal or oligoclonal cell proliferation. This lack of production of a preferential T clone in a T cell-mediated immune drug reaction implies that many T lymphocytes can recognize the antigen and be stimulated by the same drug.

Adult↗
PubMed2000

[Skin tests in the study of drug eruptions with suspected immuno-allergic mechanism].

Skin testing (patch tests, prick test and intradermal tests) with the suspected compound has been reported to be helpful in determining the cause of cutaneous adverse drug reactions (ADRs), but the value and specificity of these tests need to be determined. In a previously published study involving 72 patients, we observed positive results in 72% of the cases, in 43%, 24% and 67% in patch, prick and intradermal skin tests, respectively. The results of skin tests varied with the clinical type of cutaneous ADR, as a significantly higher number of positive patch tests was observed in maculopapular rashes (59%) than in urticarial reactions (13%) or in eythrodermic ADR (80%). The results of patch tests varied with the drug tested as frequent positive results were obtained with amoxicillin, pristinamycin, carbamazepine, pseudoephedrine, heparinoids... This study and the analysis of the literature support the value of careful sequential drug skin testing in establishing the cause of cutaneous ADR. Guidelines are proposed for performing these tests, and these include the use of appropriate negative control patients to avoid false-positive results, the determination of the relevance of positive patch tests, a contact sensitization to drug being able to elicite a positive result on patch tests with a preserved oral tolerance to the same drug. These tests have to be performed with a strict medical survey as they can induce a relapse of the cutaneous ADR.

Drug Eruptions↗
PubMed1999

C3/C4 concentration ratio reverses between colostrum and mature milk in human lactation.

The levels of complement fractions C3 and C4 were assayed in human milk in a classic nephelometric assay adapted to this secretion. Concentrations of these molecules were measured in 667 milk samples obtained sequentially from 76 volunteer lactating mothers during the first 12 weeks of lactation. Immunonephelometry was performed using skimmed milk samples diluted 10 times and yielded reproducible (coefficients of variation in within- and between-run precision lower than 9% for C3 and than 14% for C4) and accurate (linear recovery in dilution-overloading assay) data. High concentrations (mean +/- SE) were found for C3 (199.32+/-16.35 mg/L) and C4 (113.42+/-11.16 mg/L) in colostrum samples (n = 159; days 1-5). A significant (P<0.001) and rapid decrease was observed in transitional milk samples (n = 198; days 6-14), containing 57.71+/-5.18 and 72.39+/-4.98 mg/L of C3 and C4, respectively. Stable lower levels were noted in mature milk samples (n = 310; days 15-84) at 30.36+/-1.57 mg/L for C3 (P<0.001) and 53.38+/-3.61 mg/L for C4 (P<0.05). The decrease rate was different for C3 and C4, yielding a reversal of the C3/C4 ratio between colostrum and more mature milk.

Calibration↗
PubMed1999

Immunological and nutritional composition of human milk in relation to prematurity and mother's parity during the first 2 weeks of lactation.

BACKGROUND: To investigate the effect of prematurity and parity on the dynamics of the major immunologic and nutritional proteins of human milk over the first 2 weeks of lactation. METHODS: Microparticle-enhanced nephelometric immunoassays were developed for the quantification of alpha-lactalbumin, beta-casein, serum albumin, lactoferrin, and lysozyme in human milk. These components, immunoglobulin A, and total proteins were assayed in 368 individual samples collected from 74 mothers. RESULTS: The dynamics of the major immunologic and nutritional proteins in early lactation presented similar patterns in preterm and term human milks. In comparison with term milk, preterm milk was globally characterized by higher concentrations of immune proteins and lower concentrations of nutritive proteins. These differences were increased by the degree of prematurity, which, however, influenced the absolute and relative protein concentrations differently, depending on the stage of lactation. The protein composition of term milk was similar, whatever the mother's parity. Conversely, the influence of prematurity on the levels of milk proteins during the first days of lactation was even greater in primiparous mothers. CONCLUSIONS: This precise description of the composition of preterm and term milk, regarding the main nutritional and immunologic proteins, confirms the influence of both prematurity and parity on milk components and demonstrates the combined effect of these two conditions.

Female↗
PubMed1999

A baboon syndrome induced by intravenous human immunoglobulins: report of a case and immunological analysis.

Following the second series of intravenous human immunoglobulins (IVIg; 0.4 g/kg) prescribed to treat a sensorimotor polyneuritis, a 28-year-old woman developed pompholyx that recurred after each of the following monthly treatments with IVIg. During the administration of the 10th series, the patient developed a typical baboon syndrome. Immunohistochemical studies of a skin biopsy revealed an unexpected epidermal expression of P-selectin, usually expressed by endothelial cells. Patch, prick and intradermal tests performed with IVIg on the back, arms and buttocks gave negative results on immediate and delayed readings. IVIg were re-administered, with the informed consent of the patient, and induced a generalized maculopapular rash. This is the first reported case of baboon syndrome induced by IVIg. Although extensive skin testing was performed, all test sites remained negative. We wonder whether IVIg could reproduce immunological mechanisms involved in the 3 types of systemic contact dermatitis (pompholyx, baboon syndrome and maculopapular rash), including the epidermal expression of P-selectin.

Adult↗