Tissue factor coagulation pathway and blood cells activation state in renal insufficiency.

INTRODUCTION: Atherosclerotic cardiovascular disease is the leading cause of the increased morbidity and mortality observed in uremic patients. Thrombosis is an important contributor to the evolution of atherosclerotic lesions. The physiologically-relevant blood clotting depends on binding of activated factor VII (FVIIa) to exposed tissue factor (TF) on activated/damaged cells. MATERIALS AND METHODS: A cross-sectional study was performed on three age- and sex-matched groups of individuals: one group of 50 patients on maintenance hemodialysis (D group), one of 50 patients with a non-dialysed renal insufficiency (ND group) and one of 50 healthy controls (HC group). We studied basal plasma concentrations of FVIIa, factor VII-related antigen (FVIIAg), soluble TF, tissue factor pathway inhibitor (TFPI), TF-dependent circulating monocytes procoagulant activity (TF-dMPA), tissue factor-dependent plasma reactivity to activated protein C (TF-aPC), D-dimers (D-Di), and circulating markers of cellular activation/injury: soluble thrombomodulin (sTM), circulating microparticles (microP), soluble leukocyte, endothelial and platelet selectins (sL-selectin, sE-selectin, sP-selectin), soluble intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 (sICAM-1 and sVCAM-1). Their variations induced, in hemodialysis patients, by a dialysis run were thereafter studied RESULTS: Values of FVIIa, FVIIa/FVIIAg ratio, sTF, TFPI, TF-dMPA, D-Di, sTM, microP, sL, sE and sP selectins, sICAM-1 and sVCAM-1 increased all along the hierarchy HC group/ND group/D group. Microparticles were mainly of platelet origin, to a lesser extent of monocyte origin. Dialysis induced an increase of FVIIa, sTF, TF-dMPA and circulating markers of cellular activation/injury. Strong correlations were observed between FVIIa/FVIIAg ratio and serum creatinine levels, sTF, TF-dMPA, sTM, sE-selectin, sVCAM-1. The TF-aPC was impaired in the ND and the D group, and the lower values were, in the D group, associated with antecedents of vascular access thrombosis. CONCLUSION: Renal insufficiency is associated to an activation of the tissue factor coagulation pathway, to a platelet, monocyte and endothelial activation/injury and to a deficient tissue-factor induced response to activated protein C which culminate in end-stage disease and are increased by hemodialysis runs. This contributes to linked coagulation and cellular conditions for an enhanced atherosclerosis progression. Due to the TF pathway activation, the therapeutic use of recombinant TFPI should be evaluated.

Antiphospholipid and antiprotein syndromes in non-thrombotic, non-autoimmune women with unexplained recurrent primary early foetal loss. The Nîmes Obstetricians and Haematologists Study--NOHA.

Various antiphospholipid and/or antiprotein antibodies have been suspected to be associated with recurrent early foetal loss in absence of any habitual aetiology. We conducted a hospital-based case control study on women with no antecedent of thromboembolic or autoimmune disease. We studied 3 groups of 518 women: patients with unexplained primary recurrent early foetal loss, patients with explained episodes and mothers with no previous obstetrical accident. Matching the 3 groups was carried out on the basis of age, number or pregnancies and time elapsed since the end of the last pregnancy. Significant biological markers were then prospectively tested. The various antibodies were shown to be dependent on parity and on the presence of previous foetal loss: cut-off values were thus calculated using data obtained from the group of explained accidents, and adjusted for parity. Only anti-phosphatidylethanolamine IgM [odds ratio: 6.0, 95% confidence interval (2.3-15.7), p = 0.0003], anti-beta2-glycoprotein I IgG [4.4, (1.6-11.7), p = 0.0035] anti-annexin V IgG antibodies [3.2 (1.2-8.1), p = 0.015] and lupus anticoagulant [3.0, (1.3-6.8), p = 0.009], were found to be independent retrospective risk factors for unexplained early foetal loss. These four markers were subsequently found to be, during the following pregnancy, associated with a significant risk of foetal loss despite a low-dose aspirin treatment. In non-thrombotic, non-auto-immune women with unexplained primary recurrent early foetal loss, subgroups of patients with positive anti-phosphatidylethanolamine IgM antibodies, or positive anti-beta2-glycoprotein-I IgG antibodies, or positive anti-annexin V IgG antibodies or lupus anticoagulant must be particularised. This should allow therapeutic trials to be carried in well-defined patients.

Case-control study of the frequency of thrombophilic disorders in couples with late foetal loss and no thrombotic antecedent--the Nîmes Obstetricians and Haematologists Study5 (NOHA5).

BACKGROUND: Women with familial thrombophilia have an increased risk of still birth. We postulated that the presence of asymptomatic risk factors for venous thrombosis might be a risk factor for late foetal loss. METHODS: We performed a case-control study on the prevalence of heritable thrombophilic defects, of antiphospholipid-related markers and of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in patients with at least one episode of late unexplained foetal loss and in control women with successful pregnancies. Partners of cases and controls were also studied. Written conclusions of the pathological examination of the placentas, when available, were also reviewed. RESULTS: We found at least one positive biological risk factor for venous thrombosis in 21.1% of the patients and in 3.9% of the controls (p < 10(-4)). In women, the crude odds ratio for still birth associated with any positive biological risk factor for venous thrombosis was 5.5, 95% confidence interval (95%CI) [3.4-9.0]. No difference was found between partners of cases and controls (5.2% and 4.7%). Using conditional logistic regression analysis, 4 adjusted risk factors for still birth remained: protein S deficiency, positive anti beta2 glycoprotein I IgG antibodies, positive anticardiolipin IgG antibodies and the factor V Leiden mutation. The C677T mutation in the MTHFR gene was not an individual risk factor but an homozygous genotype was strongly associated with the former 4 risk factors (16.8% of patients vs. 0.9% of controls). In women with such associations, still births always occurred in absence of folic acid supplementation during pregnancy. Available conclusions of pathological analysis of placentas were found to have a very high proportion of "maternal vascular disease of the placenta" in patients with at least one positive risk marker for thromboembolism, specially in case of association with the C677T MTHFR homozygous genotype, compared to patients with negative markers (p <10(-4)). CONCLUSIONS: Late foetal loss, through placenta thrombosis, may sometimes be the consequence of a maternal multifactorial prothrombotic state associating traditional heritable or acquired thrombosis risk factors to conditions predisposing to an acute mild hyperhomocysteinaemia (coexistence of a genetic predisposition with late pregnancy-related increased folate needs).

Influence of ultrasound power on the alkylation of phenylacetonitrile under solid-liquid phase transfer catalysis conditions.

The influence of ultrasound power on the C-alkylation of phenylacetonitrile by ethyl bromide was studied under solid-liquid phase transfer catalysis in the presence of potassium hydroxide and tetrabutylammonium hydrogenosulfate. Experimental results are reported on the influence of the ultrasonic power on the yields. The optimum efficiency of ultrasounds is determined and the way in which ultrasound power may affect the yields is discussed.

The relationship between plasma microparticles, protein S and anticardiolipin antibodies in patients with human immunodeficiency virus infection.

The high prevalence of free protein S deficiency in human immunodeficiency virus (HIV)-infected patients is poorly understood. We studied 38 HIV seropositive patients. Free protein S antigen values assayed using the polyethylene-glycol precipitation technique (PEG-fS) were statistically lower in patients than in controls. These values using a specific monoclonal antibody-based ELISA (MoAb-fS) and the values of protein S activity (S-act) were not statistically different between patients and controls. C4b-binding protein values were not different from control values. In patients, PEG-fS values were lower than MoAb-fS values. Ten patients had a PEG-fS deficiency, 4 patients had a MoAb-fS deficiency and 8 had a S-act deficiency. Protein S activity and MoAb-fS were lower in clinical groups with poor prognosis and in patients with AIDS but PEG-fS was not. A trend for reduced S-act/MoAb-fS ratios was observed in patients. PEG-fS was negatively correlated with anticardiolipin antibody titers whereas MoAb-fS was not. The plasma of PEG-fS deficient HIV-patients contained high amounts of flow cytometry detectable microparticles which were depleted from plasma by PEG precipitation. The microparticles were partly CD42b and CD4 positive but CD8 negative. These micro-particles were labelled by an anti free protein S monoclonal antibody. The observed differences between MoAb-fS and PEG-fS values were correlated with the amount of detectable plasma microparticles, just like the differences between MoAb-fS and S-act. Plasma microparticles correlated with anticardiolipin antibody titers. In summary, free protein S antigen in HIV infected patients is underestimated when the PEG precipitation technique is used due to the presence of elevated levels of microparticles that bind protein S. The activity of free protein S is also impaired by high levels of microparticles. The prevalence of free protein S deficiency in HIV positive patients is lower than previously published (4/38, approximately 10%) and is correlated with poor prognosis. By implication, use of a PEG precipitation technique might give artefactually low free protein S antigen values in other patient groups if high numbers of microparticles are present. In HIV patients, high titers of anticardiolipin antibodies are associated with high concentrations of cell-derived plasma microparticles.

Effects of two low osmolality contrast media on red blood cell filterability and aggregation in vitro.

The in vitro effects of ionic ioxaglate and non-ionic iopamidol were compared. Filtration measurements were carried out on an hemorheometer; erythrocyte aggregation was evaluated by means of an erythrocyte aggregometer, and red blood cell morphology was observed with an optical microscope. Ioxaglate and iopamidol reduced erythrocyte filterability to the same extent; by contrast neither ionic nor non-ionic contrast media significantly modified aggregation or shape of red blood cells. The decrease of erythrocyte deformability observed in this study may cause clotting in catheters or syringes during angiographies investigations.

[In vitro aggregation of rat platelets by cumulative doses of trypsin: influence of aprotinin]. / Agrégation in vitro des plaquettes de Rat par doses cumulées de trypsine: influence de l'aprotinine.

As opposed to unique doses on different samples, cumulative doses of trypsin on the same rat platelet sample induced a monophasic and a more intense aggregation. Cumulative doses of trypsin were added in the presence of aprotinin, a protease inhibitor, and the curves drawn taking into account the amount of trypsin inhibited. In these conditions, the decrease of the maximum effect (Emax.) of trypsin, without change of the concentration inducing 50% of this maximum effect (EC50), suggests a non-competitive antagonism of trypsin by aprotinin on the mechanisms inducing platelet aggregation.

[Sambucus ebulus L. lectin: detection of H character of newborn red cells]. / Lectine du Sambucus ebulus L.: détection du caractère H des hématies de sang de cordon.

The O(H) foetal red cells are not always constantly agglutinated by the eel test serum, but the Sambucus ebulus L. fruit lectin provides a regular agglutination. Different experiments with treated red cells suggest that the lectin acts upon the membrane's inner sites. Besides the H sites, it is possible that other receptors might be bonded with the lectin.

Three types of mycolic acid from Mycobacterium tuberculosis Brévanne: implications for structure-function relationships in pathogenesis.

Saponification of the chloroform-soluble wax from Mycobacterium tuberculosis Brévanne led to the isolation of three classes of mycolic acid containing characteristic functional groups along the methylene backbone: type alpha (two cyclopropane rings); type beta (methoxyl, methyl, and cyclopropane); and type gamma (ketone, methyl, and cyclopropane). The structures of these acids were elucidated principally by mass spectrometry. The high mass region of the keto mycolate is presented showing the meromycolal and molecular ion regions. This is first time a molecular peak for this mycolic acid has been reported. The structure of the keto mycolate was further substantiated by study of the mass spectral fragmentation of its dithioketal derivative. Within each type of acid, a series of homologs was encountered, varying according to the number of methylene units in the backbone chain. Chromatographic and infrared spectrophotometric evidence is presented for the alkali-induced isomerization of the three types of mycolates.