bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fibrinolysis in Grafted Arteries and Veins
Authors: Risberg Bo 
Published: July 2018

SummaryThe fibrinolytic activity in autologous artery and vein grafts was studied in cats during a 4-month period. The fibrinolytic activity in the wall of an aortic segment interposed in the caval vein was increased in comparison to the normal aorta. In the corresponding segment of the caval vein interposed in the aorta, the fibrinolytic activity was reduced during the observation time. Thrombosed segments had a decreased activity. No changes were seen in sham operated animals. The plasminogen activator activity in the vessel wall was found to be influenced by the surrounding milieu.
Platelet Functions in Relation to Dietary Fats in Farmers from two Regions of France
Authors: Renaud S , Dumont E , Godsey F , Suplisson A , Thevenon C 
Published: July 2018

SummaryTo determine whether the long-term feeding of dietary fats affect platelet functions in man, platelet aggregation (to thrombin ADP, collagen, epinephrine) and clotting activity of platelet-rich plasma (PRP), platelet-poor plasma and of washed platelets, were studied in a mobile-laboratory in 44 healthy male farmers (40-45 years) from two French regions Var and Moselle, in relation to lipemia, glycemia, dietary nutriments, and platelet phospholipid composition. In the Moselle subjects, the platelet clotting activity of PRP and of washed platelets, the platelet aggregation to thrombin and ADP, were highly significantly (p <0.001) increased as compared to those of Var, but not the plasma cholesterol, which was identical in the two regions.In Moselle, the intake of total calories, total lipids and saturated fats was higher than in the Var.However, it was only with the saturated fat intake (mostly stearic acid) that the platelet clotting activity (p <0.01) and the platelet aggregation (p <0.001) were highly significantly correlated. The platelet clotting activity was also significantly (p <0.001) correlated with the fatty acid composition of the platelet phospholipid fractions phosphatidyl serine + phosphatidyl inositol.
Plasminogen Activator Inhibitor-1 Expression in Human Liver and Healthy or Atherosclerotic Vessel Walls
Authors: Chomiki N , Henry M , Alessi M C , Anfosso F , Juhan-Vague I 
Published: July 2018

SummaryIndividuals with elevated levels of plasminogen activator inhibitor type 1 are at risk of developing atherosclerosis. The mechanisms leading to increased plasma PAI-1 concentrations are not well understood. The link observed between increased PAI-1 levels and insulin resistance has lead workers to investigate the effects of insulin or triglyceride rich lipoproteins on PAI-1 production by cultured hepatocytes or endothelial cells. However, little is known about the contribution of these cells to PAI-1 production in vivo. We have studied the expression of PAI-1 in human liver sections as well as in vessel walls from different territories, by immunocytochemistry and in situ hybridization.We have observed that normal liver endothelial cells expressed PAI-1 while parenchymal cells did not. However, this fact does not refute the role of parenchymal liver cells in pathological states.In healthy vessels, PAI-1 mRNA and protein were detected primarily at the endothelium from the lumen as well as from the vasa vasorum. In normal arteries, smooth muscle cells were able to produce PAI-1 depending on the territory tested. In deeply altered vessels, PAI-1 expression was observed in neovessels scattering the lesions, in some intimal cells and in smooth muscle cells. Local increase PAI-1 mRNA described in atherosclerotic lesions could be due to the abundant neovascularization present in the lesion as well as a raised expression in smooth muscle cells. The increased PAI-1 in atherosclerosis could lead to fibrin deposit during plaque rupture contributing further to the development and progression of the lesion.
Effect of Concentration of Trisodium Citrate Anticoagulant on Calculation of the International Normalised Ratio and the International Sensitivity Index of Thromboplastin
Authors: Duncan E M , Casey C R , Duncan B M , Lloyd J V 
Published: July 2018

SummaryThe aim of this study was to determine whether the concentration of trisodium citrate used to anticoagulate blood has an effect on the INR of the sample and the ISI of the thromboplastin. Five thromboplastins including and Australian reference material were used to measure the prothrombin time of normal and patient samples collected into two concentrations of trisodium citrate - 109 mM and 129 mM. There was no effect of citrate concentration on the INRs determined with the reference material. However for the other four thromboplastins there was a significant difference between INRs for the two citrate groups. The prothrombin times of the samples collected into 129 mM were longer than those collected into 109 mM. This difference was only slight in normal plasma but more marked in patients receiving oral anticoagulants, causing the INRs for patient plasmas collected into 129 mM citrate to be higher then the corresponding samples collected into 109 mM citrate.From orthogonal regression of log prothrombin times by the reference method against each thromboplastin, we found that the ISI for each thromboplastin was approximately 10% lower when determined with samples collected into 129 mM citrate than with samples collected into 109 mM. These results suggest that the concentration of trisodium citrate used for collection of blood samples can affect the calculation of the INR and the calibration of the ISI of thromboplastin. This was found both for commercial thromboplastins prepared by tissue extraction and for a recombinant tissue factor.
Inhibition of Thrombosis by a Selective Fibrinogen Receptor Antagonist without Effect on Bleeding Time
Authors: Tschopp Juerg F , Mazur Curt , Gould Kenneth , Connolly Raymond , Pierschbacher Michael D 
Published: July 2018

SummaryMembrane glycoprotein αIIbβ3 on platelets plays a pivotal role in hemostasis by mediating RGD-(arginine-glycine-aspartic acid)-dependent platelet adhesion and aggregation. Antagonists of αIIbβ3 ligand binding function, such as antibodies, snake venom peptides, or synthetic RGD-containing peptides can completely inhibit platelet aggregation in vitro and cause significant prolongation of bleeding times when injected into experimental animals. The in vitro and in vivo properties of an αIIbβ3 specific RGD-containing peptide 2G (G(Ten)GHRGDLRCA) were compared to two non-specific RGD-containing peptides IN (G(Pen)GRGDTPCA) and 2H (GRGDSPDG). All three peptides have similar IC50 values in human patelet aggregation (14-22 μM) and ELISA-based μIIbβ3 receptor assays (0.2–0.3 αM) but show different inhibitory activity (IC50 values) in the αv㯂5 (2G = 10 μM; IN = 0.06 μM; 2H = 0.05 μM) and receptor assays (2G = 8.3 μM; IN = 0.06 μM; 2H = 0.04). The αIIbβ3 specific peptide 2G had no effect on monolayers of human saphenous vein endothelial cells while IN and 2H caused many cells to detach and contract. Peptides 2G and IN inhibited ADP-stimulated ex vivo platelet aggregation in dogs in a dose dependent manner. When complete inhibition (>90%) of ex vivo platelet aggregation was achieved with either a 10 mg/kg bolus followed by a 16mg/kg/h infusion of 2G or with a 15 mg/kg bolus and 24 mg/kg/h infusion of IN, peptide IN caused a dose-dependent increase of the template bleeding time, while peptide 2G had no effect, even at doses up to 15 mg/kg bolus followed by 24 mg/kg/h infusion. The in vivo properties of peptides 2G and 2H were also examined in a baboon ex vivo shunt model for their ability to block platelet uptake and fibrinogen deposition on small caliber GORE-TEX® grafts and for their effect on the hemostatic system. Systemic administration of peptide 2G at 10 mg/kg bolus followed by 10 mg/kg/h infusion (or at a 2-fold lower dose) abolished platelet uptake and fibrinogen deposition on the graft surface without affecting the hemostasis and template bleeding time of the animal. By contrast, peptide 2H caused a 3-4-fold increase in bleeding time at a dose of 10 mg/kg. The results suggest that efficacy and the effect of specific aIIbp3antagonists on bleeding time can be separated and that selective aIIbP3 receptor blockade may be an efficient and safe approach to improve the patency and the success rate pf small caliber vascular grafts and to treat unwanted platelet-dependent thromboses. While peptide 2G may represent a unique class of antithrombotic agent, the clinical use of this type of molecule would require a significant enhancement in potency.
Immune Tolerance in Hemophilia-Principal Results from the International Registry
Authors: Mariani G , Ghirardini A , Bellocco R 
Published: July 2018

Summary40 Hemophilia Centers from the USA, Canada, Europe and Japan referred to the International Registry 204 patients with haemophilia A, treated by Immune Tolerance (IT) Protocols over the past two decades because of the presence of an inhibitor to FVIII. 82% of the patients were high responders, while IT was started with low levels of inhibitor (<10 BU) in most (57.3%) of the cases. 69 patients (33.8%) were given the highest FVIII dosage (≥200 IU/kg/day), 71 (34.8%) intermediate dosages (50 - <200) and 64 (31.4%) the lowest dosages (<50). Of 158 patients persevering with treatment long enough to judge the outcome thereof, 107 (67.7%) achieved tolerance, 12 (7,6%) had a partial response, while 39 (24.7%) did not respond. Multivariate logistic regression analysis showed that two variables were independently associated with the highest probability of success: the use of high dose protocols (≥100 IU/kg/day) (p <.0001) and the presence of low levels of inhibitor (<10 BU) at enrollment (p = .004). The Kaplan-Meier inhibitor-free survival curve showed that tolerance is longlasting: only 1 out of 107 patients relapsed and the longest documented tolerant patient has been inhibitor-free for 16 years. 129 hemophiliacs were HIV Ab-negative at enrollment; of the 118 HIV-screened after the treatment, 18 (13.9%) were found to be HIV Ab-positive. IT can indeed modify the natural history of inhibitors to FVIII in hemophilia.
On the Rôle of Human Serum Plasminogen Activator During „Spontaneous” Activation of the Fibrinolytic System
Authors: Doleschel W , Auerswald W 
Published: July 2018

SummaryThe rôle of human plasminogen activator was studied during the “spontaneous” activation of a human euglobulin preparation at 25° and 37° C. The lytic activity of the solutions undergoing incubation was tested both on heated and on normal bovine fibrin plates. Taking into account the at least two times higher sensitivity of heated fibrin towards plasmin than of normal one as used in this investigation the respective activator activities were calculated from the diverging lytic effects on the two different types of plates. While with incubation at 25° C only low activator concentrations and slow conversion of plasminogen could be observed, at 37° C the increasing activator activity, which reached its maximum after 60 hours, was accompanied by a correspondingly fast formation of plasmin.
Macroscopie Studies of Platelet Aggregation. Nature of an Aggregating Factor in Red Blood Cells and Platelets
Authors: Øllgaard E 
Published: July 2018

SummaryIn in-vitro experiments, it has been shown that red blood cells and platelets contain a factor which, on addition to a sample of platelet-containing plasma and subsequent rocking of the test tube, causes an aggregation of the platelets which is visible to the naked eye. In equal volumes, the concentration of this factor has been found to be about 5 times as high in platelets as in red cells. The factor is thermostabile, non-protein in nature, and exerts its action independently of the process of coagulation. It is assumed to be carbohydrate in nature. White cells and, to a less degree, plasma and serum seem to be able to destroy the aggregating factor by an enzymatic process.The aggregation is reversible, since white cells as well as certain enzyme poisons and Na+ can reverse the process without any apparent change in the appearance of the platelets. The process observed thus actually seems to be a form of aggregation.
Heparin Resistance, Thromboplastin Generation and Glass Activation
Authors: Gormsen Johs 
Published: July 2018

SummarySimultaneous studies of the heparin resistance, thromboplastin generation, the partial thromboplastin time and recalcification time in normal control persons and in patients with increased heparin resistance, before and after activation with celite, appear to indicate that heparin resistance is very dependent to a factor or factor systems bound to celite.
Inhibition du Purpura Thrombopénique Immunologique par l’Acide ε-aminocaproïque
Authors: Salmon J 
Published: July 2018

RésuméL’acide ε-aminocaproïque inhibe le purpura thrombopénique immunologique. La pathogénie de ce dernier, que ne peut expliquer la seule thrombopénie, relève vraisemblablement de phénomènes fibrinolytiques, sinon d’une protéolyse non spécifique.
Influence of Blood Platelets on Fibrinolysis
Authors: Holemans Rudolf , Gross Rudolf 
Published: July 2018

Summary1. Human blood platelets contain a considerable amount of proactivator activity but no plasminogen activator activity or plasminogen. In test systems, containing streptokinase, the lysis of bovine fibrin is enhanced, depending upon the amount of platelets present.2. The platelet proactivator is completely destroyed by heating during 15 min at 70° C. Washing of platelets reduces their proactivator activity; however proactivator activity can still be found after ten washings.3. Bovine platelets do not contain proactivator activity. The similarity in the content in proactivator activity in plasma and platelets of both species, as well as the decrease of proactivator activity by washing, strongly suggests that the proactivator activity of human platelets is adsorbed on the platelet surface from the plasma.4. Both in human platelets and in bovine platelets, antifibrinolysin can be found. This factor is thermostable and is only slightly diminished by washing. The platelet antifibrinolysin seems for its larger part to be located in the platelets; only a small fraction may be adsorbed on their surface.5. The platelet antifibrinolytic activity can, depending upon the platelet concentration, be easily determined in systems containing urokinase or plasmin. Also in streptokinase-activated systems, bovine blood platelets have an inhibiting effect; human blood platelets inhibit streptokinase-induced fibrinolysis when their proactivator activity has been destroyed by heating. When streptokinase and unheated human blood platelets are tested on bovine fibrin the inhibitor effect is completely masked by the presence of proactivator.6. The clinical significance of these findings with regard to fibrinolysis occurring spontaneously or induced by streptokinase infusion, as well as their importance for the differentiation of proactivator and human plasminogen are discussed.
Effect of Surface and Hageman Factor on the Endogenous or Spontaneous Activation of the Fibrinolytic System
Authors: Iatridis Sotirios G. , Ferguson John H. 
Published: July 2018

SummaryThe effect of wettable surfaces and Hageman factor on the activation of the fibrinolytic system was investigated.The fibrinolytic activity was estimated mainly by the euglobulin lysis test. Experiments were carried out with Normal and Hageman-deficient plasmas.The euglobulin lysis time of both plasmas was greatly affected by varying the surface exposure. Normal euglobulin suspension incubated at 37° C, and tested at intervals, showed an increase of fibrinolytic activity. The evidence suggests that this activity is related to the generation of endogenous activator. The rate of generation was a function of surface. Hageman-deficient euglobulin suspension, under the same conditions, did not generate endogenous activator.Evidence is presented to show that Hageman factor is different from proactivator and plasminogen.It is concluded that wettable surfaces and Hageman factor may have a role in the endogenous (or spontaneous) activation of the fibrinolytic system.
Quantitative Determination of the Amino Acids and other Ninhydrin Positive Substances in Normal Human Platelets
Authors: Gross R , Gerok W 
Published: July 2018

SummaryIn normal human platelets twenty amino acids and additionally taurine, phosphoethanolamine and phosphoserine were determined on a quantitative basis, using elution chromatography on ion exchangers.The highest molar share goes to taurine, glutamic acid, alanine, aspartic acid, proline and serine. The other amino acids can be found in free form only in a low concentration in platelets.The connection of these results with other investigations on the metabolism is discussed.
Immunochemical Studies on Proteins Important in Blood Coagulation
Authors: Barnhart Marion I. , Erson G. F , Baker W. J 
Published: July 2018

SummaryThis report draws attention to the fact that only minute quantities of purified serum proteins (1 —15 μg/kg body weight) are required to stimulate antibody production. Injection of amounts greater than 1 mg/kg either is a waste or favors the production of non-specific antisera. Potent antisera can be produced in rabbits with a single intramuscular injection using either Al(OH)3 gel or Amphojel as an adjuvant.A number of purified plasma protein preparations which appear homogenous by ultra centrifugation or biological activity studies actually contain several antigenic components and are immunologically heterogeneous, when checked with highly specific antisera.Fibrinogen prepared by alcohol fractionation and tannic acid purification was found to be free of prothrombin, antihemophilic factor and Profibrinolysin. Both Immunoelectrophoresis and double diffusion in agar indicated a homogeneous preparation.Fibrinogens prepared from human, canine and bovine plasmas exhibited a low species specificity.
Accolement des plaquettes aux structures conjonctives périvasculaires
Authors: Hugues Jean 
Published: July 2018

RésuméCe travail est consacré à l’accolement des thrombocytes au tissu conjonctif. Les particularités de ce phénomène sont étudiées de même, partiellement, que son mécanisme.La fixation sans délai des plaquettes au tissu conjonctif périvasculaire joue vraisemblablement un rôle important dans les premiers stades dé l’hémostase.
The Measurement of Fibrinolytic Activity with I131-labelled Clots. I. The Methods
Authors: Wit C. Dudok de , Krijnen H. W , den Ottolander G. J. H 
Published: July 2018

SummaryThe technical details of a method for the measurement of fibrinolytic activity with I131-labelled clots are described. The advantages of this modification of the method of Alkjaersig are discussed.
Procedures for the Quantitative Determination of Autoprothrombin C
Authors: Cole Edmond R , Marciniak Ewa , Seegers Walter H 
Published: July 2018

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.
Molecular and Genetic Analysis of Two Patients with Bernard-Soulier Syndrome – Identification of New Mutations in Glycoprotein Ibα Gene
Authors: Kanaji Taisuke , Okamura Takashi , Kuroiwa Mika , Noda Masaaki , Fujimura Kingo L , Kuramoto Atsushi , Sano Masayuki , Nakano Shuji , Niho Yoshiyuki 
Published: July 2018

SummaryWe investigated two unrelated patients with Bernard-Soulier syndrome (BSS) by performing molecular and genetic analysis.A flow cytometric and immunoblotting analysis showed GP Ibα to be absent from the platelet membrane of both patients. Other glycoproteins that formed GP Ib/IX/V complex were present on the platelets, but in decreased amounts. Therefore, GP Ibα gene from both cases was sequenced after PCR amplification and subcloning. We identified a homozygous mutation of a dinucleotide deletion within the TGTG repeat at cDNA number 972 to 975 in GP Ibα gene from Case 1. In Case 2, compound heterozygosity was demonstrated in GP Ibα gene; an insertion of a single base (T) at cDNA number 1,418 in one allele, and a deletion of a single base (A) within the 7-adenine repeat at cDNA number 1,438 to 1,444 in another allele. The three new mutations in both patients appeared to cause a frameshift, which created a new termination codon shortly thereafter, and thus lead to a GP Ibα deficiency on the platelet membrane. Truncated mutant proteins could be detected in the plasma and platelets of Case 2, but not of Case 1. According to these findings, it is thus supposed that the properties and conformation of additional COOH-terminal peptides, which were supposedly synthesized as results of the mutations, may have an important role on the processing of mutant GP Ibα in megakaryocytes and platelets.
Prospective Evaluation of the Prevalence of Haemostasis Abnormalities in Unexplained Primary Early Recurrent Miscarriages
Authors: Gris Jean-Christophe , Ripart-Neveu Sylvie , Maugard Claude , Tailland Marie-Laure , Brun Sophie , Courtieu Christophe , Biron Christine , Hoffet Méderic , Hédon Bernard , Marés Pierre 
Published: July 2018

SummaryThe prevalence of haemostasis abnormalities was evaluated in 500 consecutive women with unexplained primary recurrent miscarriages. Two matched reference groups with no antecedent of miscarriage were studied: 100 healthy mothers and 50 childless women.In the prospective part of the study, we found 9.4% of the patients (95% C.I.: 6.8-12%) with an isolated factor XII deficiency, 7.4% of the patients (5.0-9.8%) with primary antiphopholipid antibodies, 47% of the patients (42.6-51.4%) with an insufficient response to the venous occlusion test and an isolated hypofibri- nolysis was found in 42.6% (38.2-47%) of the patients (reference groups: respectively 0/150, 3/150, 2/150, 2/150, pclO’3). Willebrand disease, fibrinogen deficiency, antithrombin, protein C or protein S deficiencies were not more frequent in recurrent aborters than in members of the reference groups. In the retrospective part of the study, cases of plasma resistance to activated protein C were not abnormally frequent.Patients had higher Willebrand factor antigen (vWF), tissue-type plasminogen activator antigen (t-PA), plasminogen activator inhibitor activity (PAI) and D-dimers (D-Di) than the reference women. Values of vWF, t-PA, PAI and D-Di were altogether correlated but were not related to C-reactive protein concentrations. Among patients, those with an antiphospholipid syndrome and those with an insufficient response to the venous occlusion test had higher vWF, t-PA, PAI and D-Di values than the patients with none of the haemostasis-related abnormalities.Thus, factor XII deficiency and hypofibrinolysis (mainly high PAI) are the most frequent haemostasis-related abnormalities found in unexplained primary recurrent aborters. In patients with antiphospholipid antibodies or hypofibrinolysis, there is a non-inflammatory ongoing chronic elevation of markers of endothelial stimulation associated with coagulation activation. This should allow to define subgroups of patients for future therapeutic trials.