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Biomedical subjects

D Arnoux

Publications and source records attributed to D Arnoux.

At least 37 records · Page 2Linked to original sources
PubMed1991

Cytofluorometric detection of human endothelial cells in whole blood using S-Endo 1 monoclonal antibody.

It has long been debated whether endothelial cells are present at very low frequency in peripheral blood. Elevated concentrations of such circulating cells may represent a good marker of vascular injury. We have therefore designed an immunocytometric assay for the detection of rare endothelial cells in whole blood. This assay is based on a new monoclonal antibody (MAb) S-Endo 1, made against human umbilical vein endothelial cells (HUVEC) and specific for endothelial cells of various origins without detectable reactivity with blood cells. First, the sensitivity of the assay was established by using normal blood samples with admixed HUVEC as an in vitro model. A good correlation was obtained between added and counted endothelial cells; the recovery was greater than 90% and the minimum detectable concentration of HUVEC was about 0.2 cells/microliters whole blood. Using this rapid counting technique, no detectable levels of endothelial cells were found in the blood of normal individuals (CE less than or equal to 0.1 cells/microliters) while elevated concentrations (up to 8 cells/microliters) were detected in a human model of vascular injury corresponding to a traumatic venepuncture. Thus, this new whole blood immunocytometric assay using S-Endo 1 MAb may be useful in determining the levels of circulating endothelial cells in vascular disorders.

Animals↗
PubMed1990

Concomitant secretion by A431 cells of tissue plasminogen activator and a specific inhibitor masks EGF modulation of tPA activity.

It has previously been reported that EGF enhances uPA but not tPA in the A431 squamous carcinoma cell line. To determine whether the absence of tPA modulation by EGF reflected steady levels or the action of an anti-activator, we assayed tPA, PAI-1 and tPA/PAI-1 complexes by zymography and immunological assays. Under conditions in which EGF had no effect on tPA activity, tPA antigen paradoxically increased with a concomitant rise of tPA/PAI-1 complexes. This indicated that tPA was rapidly inactivated through the formation of a complex, immunologically and electrophoretically related to tPA/PAI-1. tPA antigen and tPA/PAI-1 complexes were modulated by EGF in a time and concentration dependent manner. PAI-1 antigen was secreted into A431 medium (CM) after a lag phase of 16 h in both control and EGF-treated cultures. Evidence is presented here that two forms of PAI-1 are present in A431 CM: an inactive form and an active form which neutralizes the tPA secreted, masking its enhancement by EGF in functional assays.

Electrophoresis, Polyacrylamide Gel↗
PubMed1990

Acute Budd-Chiari syndrome with hepatic failure and obstruction of the inferior vena cava as presenting manifestations of hereditary protein C deficiency.

The protein C system is essential in limiting the activation of coagulation in vivo. We report on a 29 year old woman with Budd-Chiari syndrome and occlusion of the inferior vena cava who presented with acute liver failure. She was successfully treated with an emergency mesoatrial shunt. Eight months after surgery, she has no ascites and normal liver function. She had a low concentration of plasma protein C on admission to hospital and during the follow up. Protein C deficiency subsequently was found in her father and two sisters, who were asymptomatic. Hereditary protein C deficiency should be considered in patients with Budd-Chiari syndrome.

Acute Disease↗
PubMed1990

Modulation of tPA, PAI-1 and PAI-2 antigen and mRNA levels by EGF in the A431 cell line.

It has been reported that EGF treatment enhances uPA but not tPA in the A431 epidermoid carcinoma cell line. To determine whether the absence of tPA modulation by EGF could be due to the action of inhibitors, we assayed tPA, PAI-1, PAI-2 and tPA/PAI-1 complexes by immunological assays and zymography in A431 serum-free medium. We found that, under conditions in which EGF had no effect on tPA activity, tPA antigen increased with a concomitant rise of tPA/PAI-1 complexes, indicating the action of an inhibitor. Both tPA antigen and tPA/PAI-1 complexes were modulated by EGF in a time and concentration dependent manner. tPA/PAI-1 complex levels were lower than tPA levels, suggesting the presence of other inhibitors. Immunological assays detected PAI-2 in addition to PAI-1 and showed a time and dose response to EGF. Modulation of tPA and the anti-activators by the growth factor was confirmed by identification of the corresponding transcripts with cDNA probes. We conclude that the net plasminogen activator activity in A431 cells is the result of a balance between activators and inhibitors.

DNA↗
PubMed1989

Intraoperative evolution of coagulation parameters and t-PA/PAI balance in orthotopic liver transplantation.

The changes in coagulation and fibrinolysis were investigated in 10 patients undergoing orthotopic liver transplantation (OLT) which is known to be frequently associated with perturbations of haemostasis. The coagulation profile, already deteriorated before surgery in most patients, showed no appreciable further alteration. On the other hand, important modifications of fibrinolytic parameters occurred, essentially concerning tissue-type plasminogen activator (t-PA) and its specific inhibitor (PAI). t-PA activity constantly increased in the course of transplantation, reaching a maximum at the end of anhepaty. Large interindividual variations were noted in the level of t-PA activity (7.5 to 135 IU/ml). Free PAI activity followed a reverse kinetics, remaining low during the anhepatic stage, and dramatically increasing after allograft reperfusion. Despite the fibrinolytic potential related to high circulating t-PA levels, no biologic nor clinical evidence of systemic fibrinolysis was observed peroperatively. These findings suggest that PAI release could represent an early process making the use of antifibrinolytic drugs during OLT unnecessary.

Blood Coagulation Factors↗
PubMed1989

Modulation of plasminogen activator systems by matrix components in two breast cancer cell lines: MCF-7 and MDA-MB-231.

We have analyzed the plasminogen activator (PA) systems of two metastatic breast adenocarcinoma cell lines, MCF-7 and MDA-MB-231, as a function of 17 beta-estradiol stimulation when the cells were cultured on purified components of extracellular matrix. Laminin enhanced PA levels in both cell lines, but this enhancement seemed to occur via different mechanisms, including dissociation of inhibitor complexes. The major effect was the marked increase in cell-associated urokinase-type PA (u-PA); the increase was independent of estrogen in hormone-insensitive MDA-MB-231 cells grown on laminin-coated surfaces. In estrogen-sensitive MCF-7 cells, 17 beta-estradiol stimulated u-PA secretion in a similar fashion on plastic, laminin, fibronectin, or collagen but acted in synergy with laminin in the production and release of tissue-type PA.

Adenocarcinoma↗
PubMed1989

[Fibrinolytic activity in patients undergoing hepatic transplantation].

Bleeding complications during liver transplantation have been attributed to accelerated fibrinolysis. In order to determine its cause, 11 adults (mean age: 38.9 +/- 13.2 yr) undergoing liver transplantation were studied. There were three groups of patients: cirrhosis (n = 4), fulminating hepatitis (n = 4) and one group including a primary biliary cirrhosis, a hepatic metastasis and a hepatoma. The following factors were studied in the immediate preoperative period, at different surgical times throughout the procedure and 2-3 h after the end of the abdominal sutures: platelet count, prothrombin concentration, fibrinogen, activated kephalin time, factors II, V, VII + X and VIIIc, antithrombin III, protein C, D-dimers, fibrinogen and fibrin degradation products (PDF), plasma plasminogen, tissue plasminogen activator (tPA) and the fast tPA inhibitor (PAi). Preoperatively, only the two patients with hepatic cancer had a normal haemostatic profile. Throughout the procedure, all patients had only moderate changes in platelets, coagulation factors and their inhibitors, and plasminogen, because platelet concentrates and fresh frozen plasma were transfused. Levels of tPA rose, becoming very high during the anhepatic period and just after graft reperfusion. An abrupt fall occurred at the end of surgery. There were important individual differences in tPA activity. PAi activity was low during the preanhepatic and anhepatic stages, rising rapidly after revascularization.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation Factors↗
PubMed1987

Release pattern of the vascular plasminogen activator and its inhibitor in human postvenous occlusion plasma as assessed by a spectrophotometric solid-phase fibrin-tPA activity assay.

Vascular or tissue-type plasminogen activator (plasma t-PA) is the circulating physiological fibrinolytic enzyme of endothelial cell origin which function is regulated by fibrin and a specific inhibitor (PAI). To study the pattern of release of t-PA and the behavior of t-PA-PAI complexes in plasma we determined t-PA activity in 44 healthy subjects before and after 10 min of forearm venous occlusion using a new spectrophotometric solid-phase fibrin-tPA activity assay. The assay is based on 1) the high affinity binding of t-PA to fibrin, and 2) the detection of fibrin-bound t-PA by measuring the release of pNA from a chromogenic substrate in the presence of plasminogen. Values at rest were rather undetectable in plasma (0.05 +/- 0.03 IU/ml, in 23 out of 44 samples) but were positively detected in all the euglobulins: 0.88 +/- 0.68 IU/ml. After venous occlusion the majority of plasmas (36 out of 44) showed a slight increase in t-PA activity (0.65 +/- 0.63 IU/ml) as compared to the important level observed in all the euglobulins (9.78 +/- 9.58 IU/ml). So, the ratio plasma/euglobulin t-PA activity was very low (0.06) and remained identical in both pre- and postocclusion samples. However, when diluted plasmas were tested the inhibitory effect disappeared and t-PA activity increased indicating that although t-PA circulates in a neutralized state it can be available for fibrinolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Determination of factor X Ag by laser immunonephelemetry].

A method of dosage of X Ag factor by laser immunonephelemetry is proposed. This technique, carried out with a rabbit antiserum in the presence of PEG and EDTA, presents the advantage to be sensitive, reproducible and mostly faster than the other immunological methods, such as Electroimmunodiffusion (EID) and Enzyme Linked Immuno-Sorbent Assay (ELISA). It constitutes a simple tool, applicable in the demonstration of an enzyme dysfunction or liver pathology. Finally, it could bring a supplement of information in monitoring antivitamin K therapy.

Antigens↗
PubMed1986

[Spinocellular epithelioma and keratoacanthoma. Anatomicoclinical inconsistencies].

Marked prognostic differences exist between the two cutaneous lesions: squamous cell epithelioma and keratoacanthoma. The former may affect the vital prognosis while the latter usually heals spontaneously. Early diagnosis is therefore of the utmost importance, but clinico-pathologic discordances can exist when a first intention partial biopsy does not provide histologic data essential for diagnosis, or as a result of misleading clinical forms. Wide excision of these lesions is therefore an immediate necessity.

Carcinoma, Squamous Cell↗
PubMed1982

[Adolescent medicine: who cares for what?].

The expression of adolescence can be defined as a psychic maturation crisis. The purpose of this study was to better understand the specific institutional and health care needs this particular age group requires. The authors have analysed the nature of adolescent care within a pediatric ward, using data obtained from interview material. There was a growing awareness among the staff that feelings of rejection and alienation often jeopardize the delivery of optimal care to adolescents. This idea helped define the final formation of a unit designed for adolescents. The particular characteristics of such a practice are illustrated in the paper. In doing so, an effort was made to remain objective and to respect the ideas originated by the staff.

Adolescent↗