bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective PF4 Release In Vitro Induced by Heparin and Related Glycosaminoglycans (GAGs) - Correlation with β-TG Release and Platelet Aggregation
Authors: Cofrancesco E , Colombi M , Cristoforetti G , Pogliani E M 
Published: July 2018

SummaryWe studied human platelet aggregation and β-TG/PF4 release induced by heparin and related GAGs in vitro both in normal PRP and in PRP after aspirin. In our experimental conditions, heparin and related GAGs always caused PF4 release in vitro from normal platelets, whether or not there was measurable platelet aggregation in the aggregometer. Significant β-TG release was induced only by the mucosal heparin preparation (which also induced platelet aggregation in some citrated PRP). Therefore, while β-TG release in vitro seems to correlate with platelet aggregating activity of heparin, the selective PF4 release, caused by heparin and related GAGs also in conditions in which neither platelet aggregation nor β-TG are measurable, is probably associated with the high affinity of PF4 for heparin. The degree of affinity of GAGs for PF4 (heparin > DeS > HS) seems to correlate with PF4 release. Moreover, the significant reduction in PF4 release in vitro after aspirin suggests that GAGs-induced PF4 release is related to a cyclooxygenase-dependent activation process.
Dysfibrinogenemia (Fibrinogen Dusard) Associated with Impaired Fibrin-Enhanced Plasminogen Activation
Authors: Lijnen H R , Soria J , Soria C , Collen D , Caen J P 
Published: July 2018

SummaryThe fibrin-mediated enhancement of the activation of plasminogen by tissue-type plasminogen activator observed with normal fibrin, is strongly decreased with fibrin Dusard, although the binding of tissue-type plasminogen activator to this fibrin is normal. This impaired fibrin-mediated plasminogen activation is most likely related to the history of recurrent thrombosis and pulmonary embolism observed in this family.
Effects of Tris on Responses of Human and Rabbit Platelets to Aggregating Agents
Authors: Packham M A , Guccione M A , Nina M , Kinlough-Rathbone R L , Mustard J F 
Published: July 2018

SummaryDespite reports that Tris [tris(hydroxymethyl)aminomethane] affects platelets, it is often used to buffer suspending media. Human or rabbit platelets were washed and resuspended in Tyrode solution containing apyrase and 0.35% albumin. Addition of 15 mM Tris partially inhibited primary aggregation induced by 10 μM ADP and inhibited aggregation and release of 14C- serotonin from prelabelled platelets stimulated with low concentrations of thrombin (0.05-0.2 U/mL), or collagen. Platelets resuspended in 15 mM Tris, 0.15 M NaCl, 0.35% albumin, pH 7.5, did not aggregate in response to 10 μM ADP whereas platelets in Tyrode-albumin aggregated extensively. Ca2+ (5 mM) did not overcome the inhibition of thrombin-induced aggregation. Tris (15 or 1.5 mM) potentiated aggregation and release induced by sodium arachidonate (20-50 μM) or the ionophore A23187 (0.6-1 μM). Pretreatment of platelets with aspirin did not prevent potentiation by A23187, indicating that it is not mediated through activation of the arachidonate pathway. The inhibitory and potentiating effects of Tris are similar to those of amino sugars, lysine, arginine and primary amines such as methylamine and cadaverine, and may represent general effects of amines on platelets. Potentiation of the effects of some aggregating agents and inhibition of others re-emphasizes the concept that there are several different mechanisms through which aggregation can occur. Tris-based buffers are unsuitable for platelet suspending media and their use as solvents for aggregating agents or inhibitors should be limited.
Comparison Between Vascular Plasminogen Activator Activity and Changes in Blood Flow in the Renal Cortex in Pigs
Authors: Smokovitis Athanasios , Maier Manfred , Binder Bernd R 
Published: July 2018

SummaryPatterns of vascular plasminogen activator activity (PAA) and of blood flow were compared in the renal cortex of pigs. The comparison was made in pigs with or without induction of hemorrhagic hypotension and continuous infusion of indomethacin (prostaglandin synthetase inhibitor) or saralasin (competitive inhibitor of angiotensin II). Blood flow was measured by radiolabelled microspheres. A significant decrease in the vascular PAA was observed only in saralasin treated animals (15% in not hemorrhaged pigs and 30% in the inner and 45% in the outer half of the renal cortex in hemorrhaged pigs). Changes in plasmin inhibitor activity in the renal cortex were not noted. No correlation could be seen between vascular PAA and changes in blood flow in the renal cortex or changes in the mean arterial blood pressure. The vascular fibrinolytic response to saralasin should be due to an effect of saralasin independent of the changes in blood flow induced by this agent.
Mass Action Effects on Competitive Adsorption of Fibrinogen from Hemoglobin Solutions and from Plasma
Authors: Horbett Thomas A 
Published: July 2018

SummaryThe strong effect of protein adsorption on blood and tissue compatibility is well known. Little is presently known about the mechanisms which control the composition of the adsorbed protein layer which forms upon exposure of surfaces to mixtures of proteins. Reexamination of the ability of hemoglobin to inhibit the adsorption of 125I fibrinogen to polyethylene revealed that the inhibition was strongly dependent on the fibrinogen concentration. These results suggested that fibrinogen adsorption from more complex mixtures such as plasma should also be strongly dependent on total concentration. Fibrinogen adsorption from plasma was found to be maximal at intermediate plasma concentrations, and was reduced at both low and high plasma concentrations. The plasma concentration at which this maximum occurred was 10% for polytetrafluoroethylene, 1% for polyethylene, and 0.1% for glass. The unusual concentration dependence is attributed to mass action effects on the competitive adsorption of proteins, specifically that competitive effectiveness is expected to increase as unoccupied surface adsorptive sites become less frequent. Analogous effects of adsorption time on competitive adsorption are also predicted due to the changing concentration at the interface as the buffer is gradually replaced by protein solution. These mass action effects are very similar to previous qualitative observations by Vroman and are therefore dubbed the “Vroman effect”.
Selective Increases of Procoagulant Activity in Rabbit Lymphoid Populations In Vitro Following Stimulation with Endotoxin: Dependence on Anatomic Source
Authors: McGee Maria P , Rothberger Henry , Lee Tung-Kuang 
Published: July 2018

SummaryRabbit mononuclear leukocytes isolated from a variety of anatomic sites were examined for ability to generate procoagulant activity in vitro. Marrow, blood and spleen mononuclear cell populations were found to differ functionally from lymph node, thymus and alveolar populations by having much greater ability to increase in tissue factor activity in response to an endotoxin stimulus. Thus, after incubation in the presence of endotoxin, leukocytes obtained from marrow, blood, and spleen were found to increase in procoagulant activity characterized as tissue factor by 832, 1942 and 12.6 fold, respectively. In contrast, pulmonary alveolar macrophages increased in tissue factor activity only by 2.8 fold, and lymph node and thymus mononuclear cells showed little or no increases. These functional differences, demonstrated by exposing the six cell populations to endotoxin under controlled conditions in vitro, likely explain the similar pattern of anatomic selectivity of leukocyte tissue factor increases reported to occur in vivo during endotoxemia and Shwartzman reactions (1).
A Comparison of Human Pulmonary Arterial and Venous Prostacyclin and Thromboxane Synthesis- Effect of a Thromboxane Synthase Inhibitor
Authors: Carter A J , Bevan J A , Hanley S P , Morgan W E , Turner D R 
Published: July 2018

SummaryThe amounts of 6-keto-prostaglandin F1α (6-keto-PGF1α) and thromboxane B2 (TxB2) produced by the endothelial surfaces of paired samples of human pulmonary arteries and veins, obtained from patients undergoing thoracic surgery, were measured. The amounts of 6-keto-PGF1α and TxB2 produced by arteries compared with veins were not different. However, both arteries and veins produced more 6-keto-PGFlα than TxB2, the ratio being approximately 7.5:1 for both. 6-keto-PGFlα synthesis by arteries was significantly correlated with that produced by veins but the relative amounts of TxB2 were not correlated. 6-keto-PGFlα synthesis was correlated with TxB2 synthesis for veins but not for arteries. 8 of the 12 arterial samples exhibited some degree of intimal fibrosis.Incubation with the thromboxane synthase inhibitor, dazoxiben, caused a significant inhibition of vascular TxB2 synthesis and a significant increase in 6-keto-PGFlα synthesis. In 3 of the 5 cases the increase in 6-keto-PGFlα was too large to be explained by the fall in TxB2.
Influence of Vitamin E on Plasma Malondialdehyde- Like Material in Man
Authors: Cordova C , Musca A , Violi F , Alessandri C , Ghiselli A , Iuliano L , Balsano F 
Published: July 2018

SummaryThe behaviour of plasma malondialdehyde-like material (MDA-LM) was evaluated in 13 healthy subjects by a single-blind study that consisted of placebo (30 days), vitamin E treatment (300 mg/day) (30 days) and placebo (30 days). The study demonstrated that MDA-LM did not change during placebo treatment while it significantly decreased after vitamin E administration.
Evidence for the Occurrence of a Fast-Acting Inhibitor for Tissue-Type Plasminogen Activator in Human Plasma
Authors: Verheijen J H , Chang G T G , Kluft C 
Published: July 2018

SummaryHuman plasma contains a fast-acting t-PA inhibitor, which is not identical with α2-antiplasmin or α2-macroglobulin. The concentration of this inhibitor in normal plasma is highly variable, much lower than that of known plasma protease inhibitors, and in the range of physiologically occurring plasma concentrations of t- PA (0-2 IU/ml).The inhibitor binds to concanavalin A-Sepharose, is rather stable when heated, is not precipitated in euglobulin fractions and probably does not originate from platelets. The inhibitor seems to form a 190 Kd complex with t-PA. The relation between this plasma inhibitor and the recently discovered endothelial cell inhibitor is not yet clear.
Pressure-Induced Metabolic Activation of Platelets Demonstrated In Vitro by Determination of Malondialdehyde Formation
Authors: Torsellini Alessandro , Doni Luca , Palinski Wulf , Guidi Giovanni , Lombardi Valeriano 
Published: July 2018

SummaryPlatelet rich plasma (PRP) exposed in vitro to 200 mm Hg above atmospheric pressure showed a significant increase in malondialdehyde (MDA) formation compared to PRP at atmospheric pressure. This difference is also evident when platelets are incubated with arachidonic acid.The increase of MDA demonstrates that the increased beta- thromboglobulin and platelet factor 4 in plasma and the shape changes of platelets after pressure stimulation in vitro that were described in a previous paper result from the release reaction.Pressure-induced effects in vivo are discussed
Prothrombin Evaluation as Obtained by Kinetics Studies of Antigen-Antibody Reaction in a Laser Nephelometer
Authors: Girolami A , Sticchi A , Melizzi R , Saggin L , Ruzza G 
Published: July 2018

SummaryLaser nephelometry is a technique which allows the evaluation of the concentration of several serum proteins and clotting factors. By means of this technique it is also possible to study the kinetics of the reaction between antigen and antibody. We studied the kinetics of the reaction between prothrombin and an antiprothrombin antiserum using several prothrombins namely: Prothrombin Padua, prothrombin Molise, which are two congenital dysprothrombinemias, cirrhotic, coumarin or normal prothrombins. Different behaviors in the kinetics of the reactions were shown even when the concentration of prothrombins was about the same in all plasma tested. These differences were analyzed by means of a computer (Apple II 48 RAM) programmed to solve four unknown equations (Rodbard’s equation). From the data so obtained one can see that when voltages at the beginning and at the end of the reaction are in all cases about the same, a clear difference in the time required to reach half the maximum value of the voltage can still be demonstrated. This parameter, which is expressed in minutes, is longer in coumarin and prothrombin Molise than in controls. On the contrary it is shorter in prothrombin Padua and has about the same value of controls in the cirrhotic patient. Moreover the time at which the maximum rate is obtained is longer in coumarin and prothrombin Molise than in controls and shorter in liver cirrhosis and prothrombin Padua. In conclusion data obtained show that coumarin prothrombin behaves in a different way from cirrhotic prothrombin and also that there is a different behaviour between the two congenital dysprothrombinemias.
Inhibitor to Factor VIII in Mild Haemophilia
Authors: Kesteven P J , Holland L J , Lawrie A S , Savidge G F 
Published: July 2018

SummaryFactor VIII inhibitors in mild haemophilia are uncommon and the management of such patients is controversial. The development of a persistently high responding F VIII inhibitor in a mild haemophiliac is reported and the behaviour of the inhibitor discussed in the context of the various therapeutic regimes employed for symptomatic management. When inhibitor titres were low, endogenous F VIII stimulation, by DDAVP, was less immunogenic than the administration of exogenous F VIII concentrates. This inhibitor displayed characteristics of an autoantibody, and was characterised as an immunoglobulin of IgG subtype.
The Effect of Dietary Cholesterol on Platelet Survival in the Rabbit – A Study Using 14C-Serotonin and 51Chromium Double-Labelled Platelets
Authors: Wanless Ian R 
Published: July 2018

SummaryHypercholesterolemic men and monkeys have shortened platelet survival but attempts to demonstrate this in rabbits have been unsuccessful. The present study examines platelet survival in cholesterol-fed rabbits. Platelets were double-labelled in vitro with 51Cr and 14C-serotonin or in vivo by intravenous injection of 14C-serotonin.In the double-label experiments 51Cr survival was always shorter than 14C survival but changes in survival of one label were accompanied by similar changes in the other label. Survival was shortened after 4 and 7 weeks of cholesterol feeding. This was demonstrated when the donor platelets were from normal rabbits for both cholesterol and control recipients but no shortening was demonstrated when cholesterol-rich platelets were injected into cholesterol-fed recipients and normal platelets were injected into the control rabbits. When 14C-serotonin was injected intravenously 14C survival was the same as when platelets were labelled ex vivo prior to injection and 14C survival was shortened in rabbits fed cholesterol for 1,2, and 6 weeks.These results indicate that cholesterol-feeding shortens platelet survival. This effect may be masked if the test platelets are not identical in both test and control groups.
Impaired Fibrinolytic Capacity Predisposes for Recurrence of Venous Thrombosis
Authors: Korninger C , Lechner K , Niessner H , Gössinger H , Kundi M 
Published: July 2018

SummaryThe fibrinolytic capacity of 121 patients with a history of venous thrombosis and/or pulmonary embolism was studied by venous occlusion technique, at earliest 3 months after the last thromboembolic episode. After discontinuation of oral anticoagulation treatment the clinical course of the patients was followed and new thromboembolic episodes were noted. During the observation period of 56 ± 18.8 months 45 of 121 patients experienced recurrence of thrombosis. The recurrence-rate was significantly lower in patients with a post-occlusion ELT shorter than 60 min (4.8%/year) than in patients with an ELT longer than 60 min (10.3%/year). It is concluded that the fibrinolytic capacity is a useful parameter for determining the risk of recurrence in patients with venous thrombosis.
Association Between Bleeding Time and Platelet Adherence to Artery Subendothelium
Authors: Sakariassen K S , Bolhuis P A , Blombäck Margaretha , Thorell L , Blombäck Birger , Sixma J J 
Published: July 2018

SummaryThe efficacy of five different factor VUI-von Willebrand factor (FVIII-VWF) preparations in mediating adherence of blood platelets to damaged vessel walls was tested in an annular perfusion chamber utilizing human arteries and reconstituted blood.FVIII-VWF-purified by Sepharose CL-4B chromatography and von Willebrand factor prepared from this preparation by dissociation with 0.25 M CaCl2 followed by Sepharose CL-6B chromatography were equally effective in mediating platelet adherence as FVIII-VWF in cryoprecipitate and in plasma from normal subjects. A commercial concentrate of FVIII-VWF (Hemofil, Hyland) used for the treatment of haemophiliacs did not mediate platelet adherence at normal levels of FVIII-VWF related properties. A recently developed high-purity FVIII-VWF preparation (Concentrate II) containing multimers of high molecular weight normalized the platelet adherence. Platelet adherence in plasma obtained from two patients with von Willebrand’s disease (VWD) was impaired, but plasma samples obtained following treatment with Concentrate II mediated normal platelet adherence. The normalization of platelet adherence paralleled the normalization of the bleeding time.This platelet adherence assay offers an inexpensive and efficient in vitro tool to test the efficacy of FVIII-VWF preparations designed for VWD patients. Preparations such as cryoprecipitate and Concentrate II mediated the platelet adherence and normalized the bleeding time. The commercial preparation did not mediate platelet adherence and had no effect on the bleeding time.
Haemostasis in Normal Pregnancy
Authors: Stirling Yvonne , Woolf Linda , North W R S , Seghatchian M J , Meade T W 
Published: July 2018

SummaryA study has been undertaken in 72 women to provide systematic information on the changes that occur in a wide range of haemostatic variables during and after pregnancy. Factors VII, VIII :C, VIIIR:Ag, X, fibrinogen and α1 antitrypsin, rose markedly throughout pregnancy. Factors II and V and α2 macroglobulin all rose early on but then decreased steadily. Antithrombin III: C and Ag fell slightly. There was a marked decrease in fibrinolytic activity from 11-15 weeks onwards. Levels of fibrin degradation products rose from 21-25 weeks onwards. The rise in coagulation factors that occurs could be due to increased synthesis or increased activation by thrombin, or to both. The findings are consistent with a mild degree of local intravascular coagulation from early on in pregnancy in some women.
Influence of Some Plasma Fatty Acids on the Phospholipid Fatty Acid Pattern of Human Platelets – An “Ex Vivo” Experience
Authors: Vallés Juana , Aznar Justo , Santos M Teresa 
Published: July 2018

SummarySome correlations between plasma and platelet fatty acids (FA) were evaluated “ex vivo” in 94 normal subjects.The highest relationships between total FA from plasma and platelets were found for 18:1 (r = 0.74) and 18:2 (r = 0.67). Low correlations were obtained for free fatty acids (FFA). The most significant correlations between fatty acids esterifying plasma and platelet phospholipids were found for the 18:1 (r = 0.66); 18:2 (r = 0.74) and 20:5 (r = 0.66).Our results suggest that the platelet phospholipid FA could be more easily modified by plasma variation in the FA composition of phospholipids than by variations in the plasma FA composition of the FFA fraction. In addition, the incorporation of FA from plasma into the platelet phospholipids “in vivo” may take place through an acylation-deacylation process and also by the incorporation of whole plasma phospholipid molecules into the platelets, probably through an exchange of plasma lipoproteins and platelets. Finally, arachidonic acid seems to have a different and selective way of incorporation into platelet phospholipids.
Fibrinogen, Factor VIII Related Antigen, Antithrombin III and α2-Antiplasmin in Peripheral Arterial Disease
Authors: Christe M , Delley A , Marbet G A , Biland L , Duckert F 
Published: July 2018

SummaryIn 306 subjects, 217 without and 89 with peripheral arterial disease (PAD), VIIIR:Ag and α2-antiplasmin are significantly higher in PAD (p < 0.01). In the PAD negative group the ratio α2-antiplasmin/antithrombin III activity is significantly higher 1.11 ± 0.3 in the patients with an abnormal exercise ECG typical of coronary disease than in normal subjects 1.02 ± 0.2 (p < 0.05). In the PAD positive group antithrombin III concentration is higher in patients with a normal exercise ECG than in patients with abnormal exercise ECG (p < 0.05). The same is true for α2- antiplasmin but not for the antithrombin III activity. Fibrinogen and VIIIR:Ag are higher in patients with a previous myocardial infarction, however, the age is also significantly different as compared to the group without previous myocardial infarction. Disturbance of the cerebral arterial circulation is characterized by an elevation of VIIIR:Ag and of α2-antiplasmin as comapred to the values obtained in patients without this complication. There is a general tendency towards higher α2-antiplasmin values with the extension of the arterial disease.
Protein C Antigen Is Not an Acute Phase Reactant and Is often High in Ischemic Heart Disease and Diabetes
Authors: Viganò S , Mannucci P M , D’Angelo A , Gelfi C , Gensini G F , Rostagno C , Serneri G G Neri 
Published: July 2018

SummaryProtein C, an antithrombotic protein, was measured immunologically in 299 patients with clinical conditions associated with a high frequency of venous or arterial thromboembolism. The mean protein C antigen (PC: Ag) level was high for 48 patients with ischemic heart disease and, to a lesser extent, for 95 diabetics. In 28 patients with thrombotic strokes, 48 patients with proximal deep-vein thrombosis and in 80 patients with localized or metastatic tumors, mean PC: Ag was normal. Comparison of the pattern of changes of PC: Ag levels with those of fibrinogen, orosomucoid and prothrombin in 21 patients during the postoperative period and in 20 patients with active rheumatoid arthritis ruled out the possibility that high PC: Ag is non-specific, acute-phase reaction to inflammation, tissue injury or neoplastic growth. Therefore, high PC:Ag might be specifically related to the thrombotic tendency of these patients, but the mechanism of such a relationship remains to be clarified.
Quantitation by Radioimmunoassay of Thrombospondin Synthesised and Secreted by Human Endothelial Cells
Authors: Hunter N R , Dawes J , MacGregor I R , Pepper D S 
Published: July 2018

SummarySynthesis and secretion of thrombospondin by cultured human endothelial cells was quantified using a sensitive radioimmunoassay. Two endothelial lines were examined; those from umbilical veins and those from saphenous veins. The foetal line secreted ̴17 μg/106 cells of the antigen at 24 hr, whereas the saphenous line secreted five times less in the same period. Intracellular values were similar in both lines.Thrombin and calcium ionophore A23187 were added to umbilical vein endothelial cultures. In contrast to platelets where both agents cause a rapid release reaction, no such thrombospondin release was observed in endothelial cells.