bluuebunny/crossref_metadata_2025_split huggingface dataset:
Purification and Further Characterization of Antithrombin III Milano: Lack of Reactivity with Thrombin
Authors: Wolf M , Boyer-Neumann C , Meyer D , Tripodi A , Mannucci P M , Larrieu M J 
Published: June 2018

SummaryThe functional abnormality of Antithrombin III “Milano”, a previously described variant with monomeric and dimeric forms of abnormal AT III, has been further characterized. Affinity chromatography on heparin-Sepharose led to the separation and purification of two distinct tractions: fraction I is identical to normal AT III; fraction II (abnormal AT III) reproduces the abnormalities of the AT III “Milano”, i.e. lack of thrombin inhibition, incieased mobility by two-dimensional immunoclectrophoresis in the absence of heparin and migration as two bands with molecular weights of 60 K and 120 K by sodium dodecyl sulfate polyaeiylamide gel electrophoresis (SDS-PAGE). The interaction of both fiactions with purified u-thrombin was studied by the formation of complexes as well as by affinity chromatography on thrombin Seplmiose. No thrombin-AT III complexes could be demonstrated with either the monomeric or dimeric forms of purified variant AT III at both concentrations of thrombin used. Similarly, no binding to thrombin-Sepharose was observed, thus indicating that the molecular defect of AT III Milano is related to its absence of reactivity with thrombin.
Platelet Density-Dependent Partition of Platelet- von Willebrand Factor Between Alpha Granule and Non-Alpha Granule Pools
Authors: Parker R I , Shafer Brenda C , Gralnick H R 
Published: June 2018

SummaryIn this study, we demonstrate that platelets contain a small hut significant amount of platelet-von Willebrand factor(vWf) not associated with α-granules. When platelets free of plasma proteins are exposed to micromolar concentrations ofdigitonin, plasma membrane permeabilization occurs without disruption of platelet granules. Employing this technique, wehave found that upon exposure of a total platelet population to 8 μM digitonin, 5% of total platelet-vWf is released into the supernatant; this occurs without release of (β-TG from α-granules. When platelets of discrete buoyant density profiles are tested, this extragranular platelet-vWf increased with decreasing platelet density. These findings suggest that a redistribution of platelet-vWf from α-granule to non-granule sites occurs coincident with a decrease inplatelet buoyant density.
Luminography – an Alternative Assay for Detection of von Willebrand Factor Multimers
Authors: Schneppenheim R , Plendl H , Budde U 
Published: June 2018

SummaryA luminescence assay was adapted for detection of von Willebrand factor multimers subsequent to SDS-agarose gel electrophoresis and electroblotting onto nitrocellulose. The method is as fast as chromogenic detection methods and appears to be as sensitive as autoradiography without the disadvantages of the latter.
Functional Assays of Protein C: Comparison of Two Snake-Venom Assays with Two Thrombin Assays
Authors: Franchi F , Tripodi A , Valsecchi C , Mannucci P M 
Published: June 2018

SummaryProtein C (PC) activities measured by two thrombin-based assays have been compared with those obtained by two assays based on snake venom activation of plasma PC followed by measurement of both the amidolytic and anticoagulant activities of activated PC. This study indicates that snake venom assays gave results similar to those of the thrombin assays in 20 healthy subjects, in 16 patients with DIC and in 15 patients with congenital PC deficiency. There was, however, some degree of misclassification of normals and congenitally-deficient patients, with only the clotting snake venom assay resulting in no misclassifications. In 15 patients stabilized on warfarin treatment and in 17 with liver disease, the clotting snake venom assay gave significantly lower values than the other assays, so that it might prove to be more sensitive than the other assays to these defects.
Further Studies on the Mechanisms for the Antithrombotic Effects of Sulfated Polysaccharides in Rabbits
Authors: Ofosu F A , Fernandez F , Anvari N , Caranobe C , Dol F , Cadroy Y , Petitou M , Mardiguian J , Sié P , Boneu B 
Published: June 2018

SummaryA recent study (Fernandez et al., Thromb. Haemostas. 1987; 57: 286-93) demonstrated that when rabbits were injected with the minimum weight of a variety of glycosaminoglycans required to inhibit tissue factor-induced thrombus formation by —80%, exogenous thrombin was inactivated —twice as fast in the post-treatment plasmas as the pre-treatment plasmas. In this study, we investigated the relationship between inhibition of thrombus formation and the extent of thrombin inhibition ex vivo. We also investigated the relationship between inhibition of thrombus formation and inhibition of prothrombin activation ex vivo. Four sulfated polysaccharides (SPS) which influence coagulation in a variety of ways were used in this study. Unfractionated heparin and the fraction of heparin with high affinity to antithrombin III potentiate the antiproteinase activity of antithrombin III. Pentosan polysulfate potentiates the activity of heparin cofactor II. At less than 10 pg/ml of plasma, all three SPS also inhibit intrinsic prothrombin activation. The fourth agent, dermatan sulfate, potentiates the activity of heparin cofactor II but fails to inhibit intrinsic prothrombin activation even at concentrations which exceed 60 pg/ml of plasma. Inhibition of thrombus formation by each sulfated polysaccharides was linearly related to the extent of thrombin inhibition achieved ex vivo. These observations confirm the utility of catalysis of thrombin inhibition as an index for assessing antithrombotic potential of glycosaminoglycans and other sulfated polysaccharides in rabbits. With the exception of pentosan polysulfate, there was no clear relationship between inhibition of thrombus formation and inhibition of prothrombin activation ex vivo.
In Vivo Effects of a Low Molecular Weight Heparin Fragment on Platelet Aggregation and Platelet Dependent Hemostasis in Dogs
Authors: Ljungberg B , Johnsson H 
Published: June 2018

SummaryPlasma defibrinogenated dogs were used to study the influence of conventional heparin and a low molecular weight heparin fragment (Fragmin®, mean MW 5,000 d) on platelet dependent hemostasis. The heparins were given intravenously in gravimetri- cafly equal doses. The bleeding from standardized skin flap wounds and platelet aggregation (ADP and thrombin) was studied. In comparison, higher doses of the fragment than of heparin were required to increase the bleeding. ADP-induced aggregation in defibrinogenated platelet rich plasma (after addition of normal dog plasma) was potentiated by both heparins. After injection of heparin or the fragment, ADP induced platelet aggregation without prior addition of normal plasma to the testtube.In conclusion the heparin fragment affected bleeding to a less extent than conventional heparin. One explanation might be a weaker inhibition of thrombin-induced platelet aggregation.
Characterization of an In Vitro Model to Study the Permeability of Human Arterial Endothelial Cell Monolayers
Authors: Langeler Erna G , van Hinsbergh Victor W M 
Published: June 2018

SummaryA model has been developed to study the transport of fluid and macromolecules through human arterial umbilical cord endothelial cell monolayers in vitro. Cells were cultured on fibronectin- coated polycarbonate filters and formed within a few days a tight monolayer, with an electrical resistance of 17 ± 4 Ohm · cm2. The cells were connected by close cell contacts with tight junctions. The passáge-rate of horse radish peroxidase (HRP) through these filters was 20-40 fold lower than through filters without an endothelial monolayer. The continuous presence of 10% human serum was needed to maintain the electrical resistance of the monolayer and its barrier function towards macromolecules. Chelation of extracellular calcium resulted in an increased permeability and a decreased electrical resistance of the monolayer. This process was reversible by re-addition of calcium ions to the cells. The permeation rate of dextrans of various molecular weights (9-480 kD) was inversely related to the molecular mass of the molecule. No difference was measured between the passage rate of dextran of 480 kD and dextran of 2,000 kD. Incubation of the endothelial cell monolayer with 2-deoxy-D-glucose resulted in a decreased permeability but it had no effect on electrical resistance. This suggests that the passage-process is energy- dependent.Fluid permeation through the endothelial cell monolayer on filters was measured in a perfusion chamber under 20 mmHg hydrostatic pressure. It was decreased by the presence of serum proteins and responded reversibly on the chelation and readdition of extracellular calcium ions.
Increased Plasminogen Activator Inhibition Levels in Malignancy
Authors: de Jong Egbert , Knot Eduard A R , Piket Dick , Iburg Alfred H C , Rijken Dick C , Veenhof Kees H N , Dooijewaard Gerard , ten Cate Jan W 
Published: June 2018

SummaryPlasminogen activator(PA) - tissue and urokinase type - and PA-inhibition in plasma were investigated in 52 consecutive cancer patients with a variety of tumors. At first patients were analyzed as one group. Secondly patients were subdivided into two groups, one with (n = 42) and one without (n = 10) metastasis. Our results show that tissue-type-PA antigen (t-PA-antigen) and PA-inhibition were both significantly increased irrespective of the presence or absence of tumor metastasis (p <0.001) compared to age matched healthy controls. In the group without metastasis a significantly decreased level of t-PA activity was found (p <0.001) but in the group with metastasis t-PA activity was normal. These data seem to reject the hypothesis that decreased plasma fibrinolytic activity is one of the prerequisites for tumor metastasis.
Hemorrhagic Thrombocytopathy with Platelet Thromboxane A2 Receptor Abnormality: Defective Signal Transduction with Normal Binding Activity
Authors: Ushikubi Fumitaka , Okuma Minoru , Kanaji Kenji , Sugiyama Tateo , Ogorochi Toshiya , Narumiya Shuh , Uchino Haruto 
Published: June 2018

SummarySubnormal platelet responses to thromboxane A2 (TXA2) were found in a patient with polycythemia vera, and the mechanism of this dysfunction was analyzed. The patient’s platelets showed defective aggregation and release reaction to arachidonic acid, enzymatically generated TXA2 and synthetic TXA2 mimetics (STA2, U-46619). In contrast, they showed normal responses to thrombin. When the platelet TXA2 receptor was examined with both a 125I-labelled derivative of a TXA2 receptor antagonist ([125I]-PTA-OH) and a 3H-labelled TXA2 agonist ([3H]U-46619), the equilibrium dissociation rate constants (Kd) and the maximal concentrations of binding sites (Bmax) of the patient’s platelets to both ligands were within normal ranges, suggesting that the binding capacity of their TXA2 receptor was normal. STA2 failed to induce normal elevation in the. cytoplasmic free calcium ion concentration, phosphatidic acid formation and 40 kD protein phosphorylation in the patient’s platelets, whereas these responses to thrombin were within normal ranges. 12-O-Tetradecanoyl-phorbol-13-acetate (TPA) also evoked normal response in the 40 kD protein phosphorylation in the patient’s platelets. These results suggested that the patient’s platelets had TXA2 receptor abnormalities which were characterized by defective transduction of the binding signal to postreceptor reactions after normal TXA2 binding.
Effect of the Polyamine-Spermine on Agonist-Induced Human Platelet Activation - Specific Inhibition of "Aggregation-Independent" Events Induced by Thrombin, but not by Collagen, Thromboxane Mimetic, Phorbol Ester or Calcium lonophore
Authors: Joseph Sunil , Krishnamurthi Sushila , Kakkar Vijay V 
Published: June 2018

SummarySpermine, a naturally occurring polyamine, has previously been described as an inhibitor of purified phospholipase C and protein kinase C in cell-free systems. The present study examines the effect of spermine on platelet aggregation, dense-granule secretion and thromboxane (Tx) B2 synthesis induced by a variety of agonists, which cause the activation of one or both enzymes to different extents. These studies revealed that, while spermine (10 mM) inhibited platelet aggregation in response to all the agonists examined, [14C]-5-hydroxytryptamine (5HT) release and TxB2 synthesis induced by thrombin (0.2 U/ml) and collagen (10-40 μg/ml) alone, were inhibited by spermine, the percentage inhibition being >90% for both responses with thrombin, 30% for 5HT release and 80% for TxB2 synthesis with collagen. The inhibition of collagen-induced [14C]-5HT secretion by spermine was due entirely to the inhibition of aggregation-dependent TxA2 synthesis as addition of a sub-threshold concentration of U46619, which induced no secretion on its own, totally restored collagen-induced [14C]-5HT secretion to the levels seen in the absence of spermine. Moreover, collagen-induced TxB2 formation in unstirred platelets, which occurred independently of aggregation was not significantly affected by spermine (10 mM). However, the inhibition of maximal thrombin-induced [14C]-5HT secretion and TxB2 synthesis, which are both aggregation-independent phenomena, could be attributed to the inhibition of thrombin-induced diacylglycerol formation and intracellular calcium mobilization, which were both inhibited by 80% in the presence of spermine. These results suggest that spermine may be a specific inhibitor of thrombin-induced platelet responses rather than a generally effective inhibitor of platelet phospholipase C and protein kinase C or the activation of these enzymes in response to agpnists other than thrombin, at least when added exogenously to intact platelets. This thrombin-specific inhibition may be due to an interference of the binding of thrombin to its platelet receptor and/or interference at a step following thrombin binding, which is involved in the subsequent coupling processes.
Studies on Human Platelets
Authors: Booyse F. M , Zschocke Dorothea , Hoveke T. P , Rafelson M. E 
Published: June 2018

SummaryHuman platelets have been separated into 4 more homogeneous populations (A, B, C, and D; D population of highest density) by isopycnic density gradient centrifugation. Newly formed platelets have been identified in band C. These newly formed platelets age in vivo and shift into band D containing mature and old platelets. Newly formed platelets are more active in their ability to incorporate labeled amino acids into protein than mature and/or older platelets. The maturation of newly formed platelets (shift from band C to band D) is concurrent with a gradual loss in their ability to synthesize protein, a increase in density and decrease in size. In addition, newly formed platelets have a lower content of thrombosthenin than do mature (old) platelets.
“Angiokinase” - Molecular Weights of Proteins Representing a Perivascular Plasminogen Activator
Authors: Auerswald W , Binder B , Doleschel W 
Published: June 2018

SummaryBy means of gel filtration (Sephadex G-150) of precipitates originating from human cadaver vessel perfusates the molecular weights of a perivascular plasminogen activator “angiokinase” were determined. Maximum angiokinase activity was found at the molecular weight 61,000, high activities at 30,500 and 120,000, and traces of activity at 15,000, 45,700, and 76,000. Presumably angiokinase is the product of polymerization of a basic unit (mol. weight 30,500) or its subunit (mol. weight 15,000).
The Defibrination Syndrome in Rabbits Following Infusion of Tissue Thromboplastin in the Jugular Vein
Authors: Albkechtsen O. K , Brakman P , Astrup T 
Published: June 2018

SummaryThe effects of infusion of homologous tissue thromboplastin in the jugular vein of the rabbit was followed by determination of levels of coagulation factors in samples of blood obtained from the systemic arterial circulation by appropriate one-stage methods. The presence of active coagulation components was studied by appropriate two- or three-stage methods. There was marked consumption of coagulation factors, including fibrinogen. No macroscopically visible thrombi were seen in the major vessels of the systemic circulation indicating absence of tissue thromboplastin in the greater circulation. Two-and three-stage tests indicated presence of coagulation enhancing agents different from tissue thromboplastin and of a serum-like nature. Tissue thromboplastin, being bound to particulate matter, was most probably retained in the capillary bed of the lungs, thereby being prevented from appearing in the systemic circulation. The results confirm our previous findings obtained by infusion in the femoral vein. They are discussed and compared with the behavior of infused blood or tissue thromboplastin reported by other authors. Discrepancies in reported data could be traced to differences in sites of infusion or of collection of samples of blood. Changes in plasminogen concentration or in plasma euglobulin fibrinolytic activity on normal and heated fibrin plates were slight.
Streaming Potential
Authors: Edmark K.W , Davis J , Milligan H.L 
Published: June 2018

SummaryBioelectric charge transfer at the blood-wall interface may be a crucial factor affecting thrombosis on implant materials. The in-vitro streaming potential test technique offers a very sensitive, yet simple, means for observing this interfacial electrokinetic charge phenomena. Particular attention to test control variables is required, however, to obtain valid, comparative results. Due to the dynamic, changing nature of some surfaces on the molecular scale, reproducibility of results is subject to question and necessitates repeated runs to gain assurance of results.It is demonstrated that this method of evaluation is an extremely sensitive tool in the study of blood-surface inter-actions. Changes in streaming potentials are dramatically revealed upon introduction of minute quantities of blood protein elements and drugs affecting blood coagulation. The techniques for applying this test method to the study of thrombosis are illustrated.Streaming potential testing is a possible tool for realizing quality control in the preparation of anti-thrombogenic materials for cardiovascular implants. It may serve as a check, both on the formation of a proper surface and on the stability of this surface under physiological environment conditions.
Preparation and Properties of Human Prothrombin Complex
Authors: Tishkoff G. H , Williams L. C , Brown D. M 
Published: June 2018

SummaryAs a corollary to our previous studies with bovine prothrombin, we have initiated a study of human prothrombin complex. This product has been isolated in crystalline form as a barium glycoprotein interaction product. Product yields were reduced compared to bovine product due to the increased solubility of the barium glycoprotein interaction product. On occasion the crystalline complex exhibited good yields. The specific activity of the crystalline complex was 1851 Iowa u/mg. Further purification of human prothrombin complex was made by removal of barium and by chromatography on Sephadex G-100 gels. The final product evidenced multiple procoagulant activities (II, VII, IX and X). The monomeric molecular weight determined by sedimentation equilibrium in a solvent of 6 M guanidine-HCl and 0.5% mercaptoethanol was 70,191 ± 3,057 and was homogeneous with respect to molecular weight. This product was characterized in regard to physical constants and chemical composition. In general, the molecular properties of human prothrombin complex are very similar to the comparable bovine product. In some preparations a reversible proteolytic enzyme inhibitor (p-aminophenylarsonic acid) was employed in the ultrafiltration step of the purification scheme to inhibit protein degradation.
Coagulation Studies in 45 Cases of Nephrotic Syndrome without Uremia
Authors: Kanfer A , Kleinknecht D , Broyer M , Josso F 
Published: June 2018

SummaryCoagulation studies were performed in 45 cases of nephrotic syndrome without uremia. The most striking features were an increase in the number of thrombocytes, and in the level of fibrinogen, factor V and factor VIII. Thrombin time was usually prolonged and the titre of antithrombin III was increased. No fibrin breakdown products were found in the serum. 13 patients developed thrombotic complications, with eventual death in 5 cases.
Simultaneous Development of Platelet Factor 4 Activity and Release of 14C-Serotonin
Authors: Harada K , Zucker Marjorie B. 
Published: June 2018

SummaryDevelopment of platelet factor 4 activity induced under various conditions by ADP, epinephrine, or connective tissue correlated well with release of 14C-serotonin measured simultaneously. In many ways connective tissue behaved differently from ADP and epinephrine, e.g., it caused PF-4 activity and 140-serotonin release in unstirred platelet-rich plasma and was effective in platelet-rich plasma from a thrombasthenic patient whereas ADP and epinephrine were not.
Plasminogen-Fibrinogen Complex Formation as a Prelude to Fibrinogenolysis
Authors: Ball Anne P. , Silver D , Day Eugene D. 
Published: June 2018

SummaryReproducible density-gradient ultracentrifugation reference profiles of the ratezonal type were established individually for radioiodinated fibrinogen, plasminogen, and urokinase. Two- and three-component radioiodinated mixtures were then studied to determine whether stable complexes would form between any two components and thus change the density-gradient distribution profiles.Urokinase did not form stable complexes with plasminogen, fibrinogen, or fibrin, nor with any plasminogen-fibrinogen or plasminogen-fibrin mixtures.Plasminogen was found to form stable complexes with fibrinogen and with fibrin. Urokinase added to such mixtures resulted in fibrinogenolysis and fibrinolysis, but not in stable urokinase binding.The data support the proposition that urokinase does not activate plasminogen directly but requires the formation of plasminogen-fibrin(ogen) complexes as a prelude (conformational change?) to plasmin conversion and subsequent fibrin(ogen)olysis.
Die Plasma-Transglutaminase-Aktivität bei angeborenem totalem und partiellem Faktor-XIII-Mangel
Authors: Egbring R , Andrassy K , Egli H 
Published: June 2018

ZusammenfassungPatienten mit totalem Faktor-XIII-Mangel besitzen weder im Plasma noch in den Thrombozyten eine meßbare Transglutaminase-Aktivität.Heterozygote Krankheitsträger weisen als Ausdruck eines partiellen Faktor-XIII-Mangels eine verminderte Plasma-Transglutaminase-Aktivität auf.Nach Substitution von Blut oder Fraktion I nach Cohn steigt die Plasma-Transglutaminase-Aktivität an und ermöglicht eine ausreichende Fibrinstabilisierung.Auch nach Substitution zeigen die Thrombozyten bei Patienten mit Faktor-XIII-Mangel keine Transglutaminase-Aktivität.Durch Messung der Plasma-Transglutaminase-Aktivität konnten wir unsere früheren Befunde bei 2 Familien mit kongenitalem totalem bzw. partiellem Faktor-XIII-Mangel bestätigen.