Biomedical subjects

C Soria

Publications and source records attributed to C Soria.

At least 73 records · Page 4Linked to original sources

PubMed1998

Regulation of the uPAR/uPA system expressed on monocytes by the deactivating cytokines, IL-4, IL-10 and IL-13: consequences on cell adhesion to vitronectin and fibrinogen.

Urokinase (uPA) and its receptor (uPAR) have been proposed to be involved in monocyte migration by inducing degradation of matrix proteins. In addition, uPAR is also implicated in cell adhesion to the vascular wall. The adhesive function of uPAR depends on a direct interaction with vitronectin which is increased by uPA and by modification of cell surface integrin (such as CD11b-CD18) when associated to uPAR. In this study we analysed the role of three deactivating cytokines, IL-4, IL-10 and IL-13, on the surface expression of uPA, uPAR and CD11b by monocytes and their consequences on monocyte adhesion to immobilized fibrinogen and vitronectin. IL-10 induced a decrease in uPA and CD11b after 18 h incubation and a delayed decrease in uPAR which was only significant after 48 h incubation. These results may explain the decrease in monocyte adhesion, which was observed after an 18 h incubation with IL-10, on immobilized vitronectin and fibrinogen. In contrast, IL-4 and IL-13 induced a decrease in uPAR after 18 h and a significant increase in uPA both in the cell lysates and at the cell surface, as well as an increase in cell surface associated CD11b. These cytokines did not modify cell adhesiveness to vitronectin or fibrinogen despite the increase in CD11b-CD18. This could be due to the decrease in uPAR because CD11b-CD18/uPAR forms a cell adhesion complex. In addition, the increase in uPA induced by IL-4 could counterbalance the direct interaction of uPAR with vitronectin. The increase in uPA suggests that IL-4 and IL-13 could induce plaque fissuring by monocytes, whereas IL-10 may induce protection against matrix protein degradation by decreasing uPA.

Cell Adhesion↗

PubMed1998

Evaluation of a new rapid D-dimer assay for clinically suspected deep venous thrombosis (Liatest D-dimer).

In previous studies, enzyme-linked immunosorbent assays (ELISA) for plasma D-dimer analysis have demonstrated high sensitivity, suggesting their potential usefulness in excluding deep venous thrombosis (DVT). We evaluated the usefulness of a new D-dimer test (Liatest D-dimer) for suspected DVT in a prospective study of patients admitted to the hospital because of recent (not exceeding 1 week before admission) clinical signs. Contrast venography or compression ultrasonography or both were performed within 24 hours of admission. A new quantitative determination of D-dimer concentration using a suspension of microlatex particles coated with specific antibodies was tested. A standard plasma D-dimer ELISA measurement was also performed. Of 464 patients, 276 had a proven DVT (distal, 74; proximal, 202). For a cutoff level of 400 ng/mL, sensitivity of the Liatest method in the diagnosis of overall DVT was 94.6% (95% confidence interval, 92.0%-97.0%), and the specificity was 35% (95% confidence interval, 28%-42%). The sensitivity and negative predictive value were 98.5% and 95.6%, respectively, in the diagnosis of proximal DVT, but only 83.8% and 84.6%, respectively, in the diagnosis of distal DVT. This new rapid Liatest D-dimer assay seems to be highly sensitive and could replace the ELISA method in excluding patients with proximal DVT. Both methods provide lower sensitivity for distal DVT.

Autoanalysis↗

PubMed1998

In-vitro effect of oncostatin M on the release by endothelial cells of von Willebrand factor, tissue-type plasminogen activator and plasminogen activator inhibitor-1.

Epidemiological studies have demonstrated that levels of plasma fibrinogen, von Willebrand factor (vWf), plasminogen activator inhibitor-1 (PAI-1) and tissue-type plasminogen activator (tPA) are associated with the incidence of vascular disease. Since oncostatin M dramatically induces fibrinogen biosynthesis by hepatocytes and could be implicated in vascular injury leading to atherosclerosis, we have analyzed the effect of oncostatin M on PAI-1, vWf and tPA secretion by endothelial cells. A 2-h incubation of human umbilical vein endothelial cells with oncostatin M increases thrombin-induced secretion of vWf to the same extent as tumour necrosis factor-alpha or interleukin-1 (137+/-26% of control for 5 ng/ml oncostatin M, P < 0.001, n=5). The effects on tPA and PAI-1 secretion were different depending on the type of endothelial cells tested. On human umbilical vein endothelial cells, oncostatin M induced an increase in PAI-1 and a decrease in tPA secretion, which could explain the thrombogenicity of oncostatin M on large vessels. On a human microvasculature endothelial cell line, oncostatin M did not modify PAI-1 but induced an increase in tPA secretion. This observation of the effects of oncostatin M on both macro- and microvasculature could explain the increased levels of vWf, PAI-1 and tPA in the plasma of atherosclerotic subjects identified in epidemiological studies, suggesting that oncostatin M could play a key role in the development of atherosclerotic lesions.

Arteriosclerosis↗

PubMed1997

Hyaluronectin blocks the stimulatory effect of hyaluronan-derived fragments on endothelial cells during angiogenesis in vitro.

Hyaluronic acid (HA) is a glycosaminoglycan of the extracellular matrix. Its fragmentation by the hyaluronidase, secreted by tumor cells, facilitates tumor invasion and the HA degradation products generated stimulate angiogenesis. We report here that the HA-binding protein hyaluronectin (HN) inhibits the stimulatory effect of HA-derived fragments on the proliferation and migration of endothelial cells in vitro, and hampers the organization of endothelial cells into capillary-like structures. Since HN strongly inhibits endothelial cell adhesion to immobilized HA, it is postulated that HN acts by impairing the binding to endothelial cells of HA fragments generated by hyaluronidase, thereby neutralizing the effect of HA degradation products on angiogenesis. Our results reveal a new mechanism by which the angiogenesis induced by HA fragments is modulated by HN.

Animals↗

PubMed1997

Urokinase localization and activity in isolated eosinophils.

Urokinase-type plasminogen activator is implicated in cell invasion and migration. In this study, we provide evidence for the presence of urokinase-type plasminogen activator (3.5 +/- 1.5 ng/mg of cell protein) in isolated peripheral blood eosinophils, in comparison to 6.7 +/- 2.3 ng/mg of protein in neutrophils. Both immunocytochemical and immunogold staining of urokinase-type plasminogen activator on electron microscopy showed its localization in granules of resting cells. Mild stimulation by platelet-activating factor induced a translocation of urokinase-type plasminogen activator from the granules to the cell membrane and a formation of urokinase-type plasminogen activator capping, suggesting a role for urokinase-type plasminogen activator in eosinophil migration. The activation of eosinophils led to the release of factor(s) which, after activation of pro-urokinase-type plasminogen activator, induced an inactivation of generated urokinase-type plasminogen activator. Our results suggest that urokinase-type plasminogen activator is implicated in activated eosinophils invasiveness because the exposure of urokinase-type plasminogen activator is regulated both in space and time.

Biological Transport, Active↗

PubMed1997

Defective cell migration in an ovarian cancer cell line is associated with impaired urokinase-induced tyrosine phosphorylation.

The urokinase receptor (u-PAR), a protein anchored to cell membrane by a glycosyl phosphatidylinositol, plays a central role in cancer cell invasion and metastasis by binding urokinase plasminogen activator (u-PA), thereby facilitating plasminogen activation. Plasmin can promote cell migration either directly or by activating metalloproteinases that degrade some of the components of the extra cellular matrix. However, the IGR-OV1-Adria cell line contains the u-PAR but does not migrate even in the presence of exogenous u-PA, although the parental IGR-OV1 cell line migrates normally in the presence of u-PA. We therefore investigated the role of cell signalling for u-PA induced cell locomotion. We show that cell migration induced by u-PA-u-PAR complex is always associated with tyrosine kinase activation for the following reasons: (1) the blockade of the u-PAR by a chimeric molecule (albumin-ATF) inhibits not only the u-PA-induced cell migration, but also the signalling in IGR-OV1 line; (2) the binding of u-PA to u-PAR on non-migrating IGR-OV1-Adria cells was not associated with tyrosine kinase activation; (3) the inhibition of tyrosine kinase also blocked cell migration of IGR-OV1. Therefore tyrosine kinase activation seems to be essential for the u-PA-induced cell locomotion possibly by the formation of a complex u-PAR-u-PA with a protein whose transmembrane domain can ensure cell signalling. Thus, IGR-OV1 and IGR-OV1-Adria cell lines represent a good model for the analysis of the mechanism of u-PA-u-PAR-induced cell locomotion.

Blotting, Western↗

PubMed1997

Widespread cutaneous necrosis and antiphospholipid antibodies: two episodes related to surgical manipulation and urinary tract infection.

Widespread cutaneous necrosis (WCN) associated with antiphospholipid antibodies is rare. Its mechanisms have yet to be elucidated, and there are no well-established guidelines for its management. We describe a woman who had two episodes of WCN related to surgical manipulation for urinary tract obstruction and urinary tract infection. Lupus anticoagulant was always positive. In the second episode anticardiolipin antibodies were elevated, and protein C levels were temporarily decreased. We found only ten previously reported cases of WCN associated with antiphospholipid antibodies, none of which were related to surgical manipulation.

Antibodies, Anticardiolipin↗

PubMed1996

Evidence of involvement of CD44 in endothelial cell proliferation, migration and angiogenesis in vitro.

Angiogenesis is essential for tumor growth and metastasis. In the process of angiogenesis, the interaction between adhesive proteins of endothelial cells and extracellular matrix components plays an important role by mediating cell attachment, which is indispensable for their motility, and by transmitting the regulatory signals for cell locomotion and proliferation. In this study, we examined the hypothesis that CD44 expressed on the endothelial cell surface is involved in the angiogenesis process. The experiments using calf pulmonary artery endothelial cells (CPAE) and a human microvascular endothelial cell line (HMEC-1) show that a monoclonal antibody against CD44 (clone J 173) inhibits endothelial cell proliferation by about 30% and migration by 25-50%, and abolishes the stimulating effect of hyaluronan polysaccharides on endothelial cell migration and proliferation. This antibody also suppresses the capillary formation of CPAE in an in vitro model of angiogenesis using fibrin matrix. These results provide evidence of the involvement of endothelial-cell-associated CD44 in angiogenesis.

Animals↗

PubMed1996

The relationship between the fibrinogen D domain self-association/cross-linking site (gammaXL) and the fibrinogen Dusart abnormality (Aalpha R554C-albumin): clues to thrombophilia in the "Dusart syndrome".

Cross-linking of fibrinogen at its COOH-terminal gamma chain cross-linking site occurs in the presence of factor XIIIa due to self-association at a constitutive D domain site ("gammaXL"). We investigated the contribution of COOH-terminal regions of fibrinogen Aalpha chains to the gammaXL site by comparing the gamma chain cross-linking rate of intact fibrinogen (fraction I-2) with that of plasma fraction I-9, plasmic fraction I-9D, and plasmic fragment D1, which lack COOH-terminal Aalpha chain regions comprising approximately 100, approximately 390, and 413 residues, respectively. The cross-linking rates were I-2 > I-9 > 1-9D = D1, and indicated that the terminal 100 or more Aalpha chain residues enhance gammaXL site association. Fibrinogen Dusart, whose structural abnormality is in the COOH-terminal "alphaC" region of its Aalpha chain (Aalpha R554C-albumin), is associated with thrombophilia ("Dusart Syndrome"), and is characterized functionally by defective fibrin polymerization and clot structure, and reduced plasminogen binding and tPA-induced fibrinolysis. In the presence of XIIIa, the Dusart fibrinogen gamma chain cross-linking rate was about twice that of normal, but was normalized in proteolytic fibrinogen derivatives lacking the Aalpha chain abnormality, as was reduced plasminogen binding. Electron microscopy showed that albumin-bound Dusart fibrinogen "alphaC" regions were located in the vicinity of D domains, rather than at their expected tethered location near the fibrinogen E domain. In addition, there was considerable fibrinogen aggregation that was attributable to increased intermolecular COOH-terminal Aalpha chain associations promoted by untethered Dusart fibrinogen aC domains. We conclude that enhanced Dusart fibrinogen self-assembly is mediated through its abnormal alphaC domains, leads to increased gammaXL self-association and gamma chain cross-linking potential, and contributes to the thrombophilia that characterizes the "Dusart Syndrome."

Dextrans↗

PubMed1996

Blockage of urokinase receptor reduces in vitro the motility and the deformability of endothelial cells.

The binding of urokinase (u-PA) to its cell surface receptor (u-PAR) is critical for tumor cell invasion. Here, we report that the distribution of this binding by a u-PAR antagonist ATF-HSA inhibits in vitro the motility of endothelial cells in a dose-dependent manner. This inhibition was also observed when the cells were first stimulated with potent angiogenic factors, including bFGF or VEGF. [3H]thymidine incorporation assay demonstrated that ATF-HSA did not affect the cell proliferation. ATF-HSA was more potent than plasmin inhibitors, suggesting that it exerts its effects not solely by inhibiting the remodeling of the extracellular matrix. In fact, analysis of the cell shape change during migration revealed for the first time that its effect is related to a decrease in cell deformability. These results suggest that u-PAR antagonist may be a new approach to control angiogenesis.

Aprotinin↗

PubMed1996

Fibrinogen binding and platelet retention: relationship with the thrombogenicity of catheters.

One of the major problems in the use of catheters is their thrombogenicity, since the embolization of clots near the central nervous system or the coronary arteries can cause permanent damage. In this work we have compared the in vivo thrombogenicity of four different angiography catheters and their in vitro activation of fibrinogen binding and platelet retention. The thrombogenicity of catheters has been evaluated in angiographic conditions by kinetic evaluation of the reduction of blood flow rate through the catheters. The binding of adhesive proteins (fibrinogen and von Willebrand factor [vWF] was studied in vitro using a direct-ELISA technique after circulation of anticoagulated whole blood through sections of catheters. The retention of platelets was studied in vitro using 111Indium-labelled platelets. Fibrinogen binding and platelet retention both seem to be good predictors of catheter thrombogenicity, fibrinogen being the better of the two. The most thrombogenic material has the highest fibrinogen and platelet retention rate. This study also confirms the inefficiency of albumin precoating for the prevention of fibrinogen deposition. The determination of fibrinogen deposition by direct-ELISA technique and platelet retention rate is very useful for preclinical testing of catheters.

Biocompatible Materials↗

PubMed1996

Fibrinogen Dusart: electron microscopy of molecules, fibers and clots, and viscoelastic properties of clots.

Ultrastructural perturbations resulting from defects in polymerization of fibrinogen Dusart, a congenital dysfibrinogenemia with the amino acid substitution A alpha 554 arginine to cysteine, were investigated by a variety of electron microscope studies. Polymerization of this mutant fibrinogen on addition of thrombin is impaired, producing clots with decreased porosity and increased resistance to fibrinolysis, resulting in thrombotic complications in the family members with this dysfibrinogenemia. Electron microscopy of rotary-shadowed individual molecules revealed that, in contrast to control fibrinogen, most of the alpha C domains of fibrinogen or fibrin Dusart appeared to be free-swimming appendages that do not exhibit intra- or intermolecular interactions either with each other or with the central domains. The location of albumin on the alpha C domains was demonstrated by electron microscopy using anti-albumin antibodies. Electron microscopy of negatively contrasted fibrin Dusart fibers indicated that they were less ordered than control fibers and had additional mass visible. Electron microscopy of freeze-dried, unidirectionally shadowed fibers showed that they were twisted with a shorter pitch. Scanning electron microscopy revealed that intact clots were made up of thin fibers with many branch points and very small pore sizes. The viscoelastic properties of Dusart fibrin clots measured with a torsion pendulum indicated a marked increase in stiffness consistent with the structural observations.

Biomechanical Phenomena↗

PubMed1996

Down-regulation of fibrinogen biosynthesis by IL-4, IL-10 and IL-13.

High levels of fibrinogen are recognized as an important vascular risk factor; however, it is not known if the increase of plasma fibrinogen is directly responsible for this risk, or is only a marker of vascular inflammation. To support this second hypothesis, Oncostatin M (OSM) is a potent stimulator of fibrinogen biosynthesis and induces smooth muscle cell proliferation. In the same way, we analysed whether interleukin-4 (IL-4), interleukin-10 (IL-10) or interleukin-13 (IL-13), which protect vessel walls from monocytes injuries leading to atherosclerosis, could influence fibrinogen biosynthesis. The two levels of regulation of fibrinogen biosynthesis were tested: firstly, the direct effect of these cytokines on fibrinogen production by the hepatoma cell line Hep G2, and secondly their effect on the secretion of hepatocyte stimulating factor (HSF) activity in the supernatant of lipopolysaccharide (LPS)-activated monocytes. IL-4 and IL-13 added to Hep G2 cells down-regulated both the increase of fibrinogen secretion induced by IL-6 and fibrinogen mRNA levels, this effect being more pronounced when Hep G2 were preincubated with the two cytokines before IL-6 addition. The effect of IL-10 was evidenced only on mRNA expression. IL-10 and IL-13 dose-dependently decrease HSF activity secreted by LPS-activated monocytes, whereas IL-4 had no effect. However, the three cytokines decreased HSF activity when monocytes were incubated with the cytokines before LPS activation. The effects of these cytokines on HSF activity are related to variations of IL-6 and OSM secretion. Our data strengthen the hypothesis that the fibrinogen level is a marker of vascular disease, since cytokines which have a protective vascular effect down-regulate fibrinogen production.

Animals↗

PubMed1996

Regulation of fibrinogen biosynthesis by cytokines, consequences on the vascular risk.

High level of fibrinogen in plasma is recognised as an important vascular risk factor. However, it is not known if the increase in fibrinogen is directly responsible for the vascular risk or is a marker of vascular inflammation. Our data strengthen the hypothesis that the fibrinogen level is a marker of vascular disease, since a parallel effect of cytokines on fibrinogen biosynthesis and on vascular injury was noted. Among the cytokines which induce the synthesis of fibrinogen, oncostatin M (OSM) is the most potent cytokine synthesised by activated monocytes for inducing fibrinogen synthesis by Hep G2 cells (human hepatoma cell line). Interestingly at the same concentrations needed for fibrinogen biosynthesis, OSM induces smooth muscle cell proliferation. In contrast, the cytokines IL-4, IL-10 and IL-13 which have a protective effect against vascular injury leading to atherosclerosis, dose dependently down regulate the biosynthesis of fibrinogen. This was due to both a decrease of IL-6 induced fibrinogen synthesis by hepatocytes, evidenced by a decrease in fibrinogen secretion in the medium and beta chain mRNA expression and to an inhibition of production of the hepatocyte-stimulating activity for fibrinogen biosynthesis (HSF) by LPS-activated monocytes. Noteworthingly, IL-10 induces a significant decrease of the production of OSM by LPS-activated monocytes. In situ activation of monocytes by cytokines in the vessel wall could also contribute to the deposition of fibrin(ogen) derivatives, identified as pathogenic factor.

Arteriosclerosis↗

PubMed1995

An autoradiographical saturation kinetic study of the different benzodiazepine binding sites in rat brain by using [3H] flunitrazepam as a radioligand.

The present study reports on the equilibrium association constant (KD) and receptor density (Bmax) values of a number of brain areas from the mesencephalon, cerebral cortex, hippocampus, and cerebellum for the overall benzodiazepine (BZ) binding sites as well as for benzodiazepine binding site subtype 1 (BZ1) and subtype 2 (BZ2), determined by autoradiographical procedures using [3H] flunitrazepam. The differences between BZ1 and BZ2 binding sites were analyzed using the specific BZ1 agonist zolpidem as inhibitor of the radioligand. Statistically significant differences in the affinities of BZ2 with respect to BZ and BZ1 binding site were mainly found in cortical layers when pKD (negative logarithms of KD values) values were compared (ANOVA-SNK test). The distribution of Bmax, as well as the percentages of BZ1 and BZ2 and Hill coefficients which, surprisingly, are always close to 1 (> 0.9) for all the saturation kinetics analyzed, are also described. The possibility of heterogeneity related to anatomical distribution in the different subtypes is discussed.

Analysis of Variance↗

PubMed1995

The effect of platelets on invasiveness and protease production of human mammary tumor cells.

Interaction of tumor cells with platelets facilitates metastasis of tumor cells. It has been proposed that platelets protect tumor cells against the host's immune defense and enhance tumor-cell extravasation. In the present work we show that platelets increase the invasiveness of 3 mammalian cell lines (MCF-7, ZR-51 and MDA-MB231) through extracellular matrix, and propose this as an additional mechanism by which platelets facilitate metastasis. Since gelatinase and urokinase have both been implicated in degradation of the extracellular matrix and cell migration, and therefore in tumor invasion, we have also analyzed whether the interaction of platelets with tumor cells can modify the secretion of these proteases by tumor cells. MDA-MB231, which was the most invasive cell line among the 3 tested and was the most potent in inducing platelet aggregation, secreted the highest level of urokinase and was the only one in which gelatinase was detected. While platelets had no significant effect on the urokinase activity expressed by these cells, they induced in MDA-MB231 an important increase in the secretion of gelatinase, which can be reproduced by both platelet membrane and platelet releasate of activated platelets. This increase in gelatinase could be responsible, at least in part, for the increased invasiveness of these cells, since added TIMP-1 significantly reduced the number of cells which traversed matrigel.

Blood Platelets↗

PubMed1995

Expression of elastase and fibrin in venous leg ulcer biopsies: a pilot study of pentoxifylline versus placebo.

The pathogenesis of venous leg ulcers is based on the leakage of fibrinogen leading to a pericapillary fibrin cuff and plugging of capillaries by white blood cells. On the basis of a previous work, we had assumed that the key event in the pathogenesis of venous leg ulcers is related to inflammation generated by activated white blood cells that accumulate under unrelieved blood pressure, because in ulcer biopsies we had detected the presence of tumor necrosis factor-alpha (TNF-alpha) in intracapillary monocytes, elastase in the polymorphonuclear leukocytes near the vessels, and a pericapillary undegraded fibrin cuff causing a diffusion barrier to oxygen. This concept was developed because TNF-alpha synthesized by activated monocytes is responsible for many deleterious effects. It has a potent mitogenic effect on fibroblasts, leading to new collagen deposition and angiogenesis, it induces an increase in collagenase production, it acts through upregulation of an intracellular adhesion molecule (ICAM-1), leading to leukocyte sequestration and consequently a release of toxic metabolites by the polymorphonuclear cells, an early step in chronic inflammation, it activates the coagulation pathway via a marked increase in monocyte-associated tissue factor (TF) procoagulant activity, and it inhibits fibrinolysis by promoting the release of PAI-1, contributing to undegraded fibrin deposition. Therefore, we were interested in evaluating, in patients with venous leg ulcers, the effect of pentoxifylline administered at 1,200 mg daily (versus placebo) for 2-months, as this drug induces a decrease in TNF-alpha synthesis and also blocks its activity. This pilot assay was performed in blind. Evolution of several parameters in ulcer biopsies are analyzed: TNF-alpha, intact fibrin, fibrin degradation products, ICAM-1, TF, and elastase. Pentoxifylline administration induced a decrease of local elastase and of fibrin deposit. These results support the hypothesis that accumulation of activated leukocytes is the key event in venous leg ulcers.

Antibodies, Monoclonal↗

PubMed1995

Severe arterial thrombosis in a congenitally factor VII deficient patient.

We report a patient with congenital factor VII deficiency who developed severe arterial thrombosis. A 63-year-old-woman presented low factor VII clotting activity, amidolytic activity and antigen level < 4%. Activated factor VII plasmatic level was < 0.03 ng/ml compared to 4 ng/ml for the control value. She developed severe aorto-iliac thrombosis. 7 d before the thrombotic event, factor VII replacement therapy had been infused. Successful low molecular weight heparin therapy led to total disappearance of the aorto-iliac thrombus without bleeding complications. This suggests that factor VII infusion might have a thrombogenic effect in vivo and might be responsible for thrombosis.

Aortic Diseases↗