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Background:  Heparin-induced thrombocytopenia (HIT) is a rare complication of heparin treatments, and only a few large patient cohorts have been reported. In this study, biological and clinical data from 144 French patients with HIT were analyzed in comparison with the literature., Methods:  The diagnosis of HIT was confirmed in all patients by an immunoassay combined with serotonin release assay. In the literature, only cohorts of at least 20 HIT patients published from 1992 were selected for a comparative analysis., Results:  Two-thirds of patients were hospitalized in surgery and most were treated with unfractionated heparin (83.2% vs. 16.8% with low molecular weight heparin only). Thrombotic events in 54 patients (39.7%) were mainly venous (41/54). However, arterial thrombosis was more frequent after cardiac surgery (13.2% vs. 2.4% in other surgeries, p  = 0.042) with a shorter recovery time (median = 3 vs. 5 days, p  < 0.001). The mortality rate was lower in our series than in the 22 selected published studies (median = 6.3% vs. 15.9%). Three genetic polymorphisms were also studied and homozygous subjects FcγRIIA RR were more frequent in patients with thrombosis (37.8 vs. 18.2% in those without thrombosis, p  = 0.03)., Conclusion:  This study shows that the mortality rate due to HIT has recently decreased in France, possibly due to earlier diagnosis and improved medical care. It also confirms the strong association between polymorphism FcγRIIA H131R and thrombosis in HIT., Competing Interests: Y.G.: Consulting and/or travel fees from Octapharma, Shire, CSL Behring, Novo Nordisk, Bayer, LFB, and Léo Pharma. J.R.: Travel fees from Octapharma, Shire, and CSL Behring. C.V.: Travel fees from Sobi, Roche, Shire, and CSL Behring. D.F.: Consulting and/or travel fees from Aspen, Boehringer, Werfen, Stago, and Léo Pharma. A.B.: Travel fees from Aspen, Boehringer, Werfen, Pfizer, and LFB. A.L.: Consulting and/or travel fees from Bayer, LFB, Pfizer, Sobi, and Octapharma. E.D.M.: Travel fees from Sobi, Bayer, Novo Nordisk, and Pfizer. B.T.P.: Consulting and/or travel fees from Sobi, Bayer, Shire, CSL Behring, and Pfizer. I.E.: Consulting and/or travel fees from BMS, Aspen, Léo Pharma, Daiichi Sankyo, Pfizer, Sanofi-Aventis, and Shire. C.L.B.: Travel fees from Sobi, Octapharma, CSL Berhing, and Novo Nordisk. C.M.: Consulting and/or travel fees from BMS, Aspen, Pfizer, and Bayer. C.B.: Consulting and/or travel fees from CSL, Sobi, Bayer, and Novo Nordisk. C.T.: Consulting and travel fees from Sobi, Roche, Octapharma. F.N.G.: Travel fees from Sobi, Bayer, BMS, and Boehringer. J.D.: Travel fees from CSL and Novo Nordisk. T.B.A.: Travel fees from Servier and MSD. E.D.R.: Consulting and/or travel fees from Shire, Alexion, Sobi, Bayer, and Novo Nordisk. I.G.T.: Consulting and/or travel fees from Bayer, MSD, Pfizer, Sanofi-Aventis, and BMS. L.R.: Consulting and/or travel fees from CSL, LFB, Novo Nordisk, Sobi, and Bayer. B.T.: Consulting and/or travel fees from Sobi, Bayer, Novo Nordisk Aspen, CSL Behring, and Pfizer. C.P.: Consulting and/or travel fees from Sobi, Roche, Novo Nordisk, and CSL Behring. P.W., M.A.G., S.V., V.G.G., J.P., and B.G. have no conflict to disclose. All the authors did not receive any personal honorarium or funds related to the study reported in this manuscript. Y.G. reports grants from Ministère de la Santé (Government), during the conduct of the study; personal fees and nonfinancial support from CSL Behring, personal fees and nonfinancial support from Octapharma, nonfinancial support from Shire, personal fees from Léo Pharma, personal fees and nonfinancial support from LFB, nonfinancial support from Bayer, nonfinancial support from Novo Nordisk, outside the submitted work., (Georg Thieme Verlag KG Stuttgart · New York.)

Background:  Ligneous conjunctivitis (LC) is a rare disorder associated with plasminogen deficiency characterized by chronic fibrin deposits in the eyelids. All patients with plasminogen deficiency do not develop LC, whose underlying mechanisms remain unknown., Objective:  We investigated whether fibrinolytic activity was correlated with phenotype and/or genotype in patients suffering from LC and their relatives., Methods:  Plasminogen activity/antigen levels and PLG mutations were determined in 10 patients with LC, 17 of their asymptomatic relatives, and 10 healthy individuals used as a control group. Plasma fibrinolytic activity was evaluated using three different assays: (1) tissue-plasminogen activator (t-PA) front lysis, (2) cell-based urokinase-dependent euglobulin clot lysis (ECLT) at the surface of corneal cells, and (3) urokinase-dependent plasminogen activation., Results:  Plasminogen activity varied from <10 to 40% in patients, 36 to 105% in relatives, and >80% in control healthy individuals. Homozygous K19E mutation was associated with normal antigenic plasminogen levels. In front-lysis experiments, all patients had a lower fibrinolysis rate as compared with their relatives and to control individuals. The cell-based ECLT and plasminogen activation assay demonstrated that urokinase-mediated fibrinolysis was not impaired in patients with homozygous K19E mutation compared with the other mutants., Conclusion:  We confirm that plasminogen levels fail to predict LC occurrence. In these conditions, t-PA clot lysis front is useful to predict clinical outcome in plasminogen deficiency. Moreover, we provide evidence that occurrence of LC overlaps quantitative and qualitative plasminogen deficiencies. The homozygous K19E mutation is associated with isolated impaired t-PA-mediated fibrinolysis compared with other mutants., Competing Interests: None declared., (Georg Thieme Verlag KG Stuttgart · New York.)

We have identified a novel heterozygous fibrinogen gamma chain mutation, gammaN345S (Fibrinogen Saint-Germain II), in a subject with hypofibrinogenemia. There was no evidence by mass spectrometry of plasma fibrinogen containing the mutant chain. The hypofibrinogenemia was discovered in a 26-year-old man who experienced extensive deep venous thrombosis of the left leg associated with pulmonary embolism. Investigation of potential thromboembolic risk factors revealed heterozygosity of the factor V R506Q mutation (factor V Leiden) and heterozygosity of the prothrombin gene G20210A mutation. The hypofibrinogenemia may be contributory to the thrombophilic manifestations.

Limited proteolysis of human alpha-thrombin by various proteases has been efficiently used to demonstrate the importance of two insertion loops located on the surface of this molecule. In the present study, we demonstrate that two-chain urokinase (tcu-PA) specifically cleaves the B chain of alpha-thrombin giving rise to a transient derivative, consisting of two non-covalently linked subunits. Although the thrombin derivative conserves its activity towards the synthetic substrate S-2238 (Km = 8.4 microM and kcat = 145 s-1 versus respectively 4.5 microM and 149 s-1 for alpha-thrombin), most of its coagulant activity is lost (140 NIH u/mg versus 3000 NIH u/mg) and its ability to activate platelets is considerably reduced (threshold for full platelet aggregation 2.5 nM versus 0.25 nM). The thrombin fragments were separated by HPLC and after reduction and S-carboxyamidemethylation were digested with a lysylendopeptidase; the resulting peptides were separated by HPLC and sequenced. One fragment corresponded to B chain fragment 1-73 and the second to B chain fragment 74-259 covalently linked to the A chain, indicating that tcu-PA cleaves selectively the peptide bond Arg 73-Asn 74 in the B chain. The proteolytic derivative obtained, designated beta u-thrombin, is therefore identical to the transient proteolytic derivative, beta 1-thrombin, produced by trypsin. Prolonged incubation with tcu-PA resulted in further conversion in a derivative analogous to gamma t-thrombin.(ABSTRACT TRUNCATED AT 250 WORDS)