bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of the Platelet Response to Laserinduced Microvascular Injury
Authors: Hovig T , McKenzie F. N , Arfors K.-E 
Published: June 2018

SummaryMicrovascular injury was produced in rabbit mesentery and ear chamber preparations using a biolaser. Ultrastructural studies of the injury sites revealed damage to the endothelium which showed cytoplasmic swelling and flocculation. Complete destruction of the endothelium was not observed, indicating that sub endothelial structures were not exposed to blood flow. Microvascular thrombi which occurred at the sites of injury were composed of platelets which in general were loosely packed and showed minor alterations in shape and internal structure. Erythrocytes appeared to be heavily damaged by the laser injury. Fibrin was not observed. It is concluded that ADP may be released from red blood cells, and possibly from other sources, as a result of the laser injury, and that the platelet thrombus formation is induced by ADP.
The Plasminogen-Plasmin System Part VIII On the Mechanism of Chemical Induction of Fibrinolysis Isolation of a Latent Plasminogen Activator from Human Plasma
Authors: Tomikawa Munehiro , Abiko Yasushi 
Published: June 2018

SummaryA component, responsible for the chemical induction of fibrinolysis by flufenamate, was isolated from human plasma. The isolation procedures included removal of euglobulin precipitate from plasma, Sephadex G-200 gel filtration of the euglobulin- supernatant fraction and isoelectric focusing. The partially purified component was immunologically distinct from ßioglobulin, plasmin and plasminogen. Plasminogen activator activity was liberated from the component by treatment with flufenamate. The mechanism of induction of fibrinolysis by flufenamate is discussed.
Factors Regulating Plasma Protein Synthesis
Authors: Bocci V , Pacini A 
Published: June 2018

SummaryThe intravenous injection of a large amount of homologous fibrinogen in the rabbit produces typical changes in the level of circulating fibrinogen. The first peak is due to the administered fibrinogen while the second, occurring after 16 hr, is interpreted as being due to the stimulation of hepatic synthesis and release of preformed fibrinogen. This typical profile was obtained with different fibrinogen preparations but not with heterologous fibrinogen. Neither was it obtained after administration of homologous γ-globulin, α-globulin or albumin. Assuming that enhancement of hepatic synthesis might be due to fibrinogenolytic products, the effect of the injection of fibrinogen digest products (FDP) was investigated. Administration of homologous FDP causes, within 24 hours, a significant increase of the plasma fibrinogen level. The critical requirement of injecting either the protein solution or saline intravenously rather than subcutaneously is emphasized. In conclusion, FDP appear to be endowed with the novel property of stimulating fibrinogen synthesis and possibly of causing the release of preformed fibrinogen.
Amount of Fibrin in Different Organs after Intravenous, Intraportal and Intraaortal Injection of Thrombin in the Rat
Authors: Busch Christer , Saldeen Tom 
Published: June 2018

SummaryThe effect of intravenous, intraaortal and intraportal injection of thrombin on the distribution of intra vascular fibrin in various organs was determined by a quantitative method in the rat. It was found that the major part of the fibrin was trapped in the lungs irrespective of the route of administration of the thrombin.These results suggest that in thrombin induced intravascular coagulation most of the coagulation occurs on the venous side of the circulation.This mechanism may be an explanation for the fact that certain organs more often contain intravascular fibrin than others at autopsy.
Ethanol Gelation and Protamine Sulfate Tests
Authors: Jacobsen Carl D. , Southers Nancy J. 
Published: June 2018

SummaryPlasmas collected with Trasylol and EACA were studied for fibrin formation in the ethanol gelation and protamine sulfate tests. The latter test was difficult to read and a solid gel was rarely found, even when a definite solid gel was apparent in the ethanol gelation method. The protamine sulfate test is also said to record split products of fibrin. However, if hirudin was added to mixtures of plasma and fibrin digestion products, protamine sulfate did not cause gel formation, indicating that thrombin (or formation of thrombin) was necessary also for the gel formation induced by split products.The protamine sulfate and ethanol gelation tests have several limitations. Care should be taken to avoid uncritical interpretations of results obtained with these tests.
Cold Promoted Activation of Factor VII
Authors: GJØNNÆSS H 
Published: June 2018

SummarySpontaneous cold promoted activation of factor VII was independent of the fibrinolytic activity of plasma and caused no activation of plasminogen.After the spontaneous cold activation a highly significant increase in the proteolytic capacity was observed which was not seen after induced cold activation.Cold activation induced with known prekallikrein activators (EACA, kaolin, Li- quoid) or with a semipurified plasma kallikrein preparation was independent of the fibrinolytic activity of plasma and caused no change in this.Cold activation induced with urokinase and with streptokinase was probably mediated by plasmin. The urokinase induced activation of plasminogen was independent of factor XII, whereas this factor was a prerequisite for the cold activation of factor VII.The urokinase induced cold activation of factor VII correlated with increased TAME - esterolytic activity and an 80 per cent decrease of the kininogen concentration, indicating activation of the plasma kallikrein system.
The Effect of Some Platelet Aggregating and Potential Thrombosis-Promoting Substances on the Development of Experimental Arterial Thrombosis
Authors: Hladovec J 
Published: June 2018

SummaryA series of platelet aggregating or potentially thrombosis-promoting agents was administered intravenously 1 minute before the electric provocation of thrombosis in the carotid artery of the rat. Adenosine diphosphate, adrenaline, thrombin, ellagic acid, tannin, ε-aminocaproic acid and Trasylol were ineffective in shortening the time of thrombosis. On the contrary, most of these drugs showed some antithrombotic effect. Only 5-hydroxytryptamine definitely potentiated the process of thrombosis.
The Determination of Platelet Aggregation by Filtration Pressure in Circulating Dog Blood
Authors: Broersma R. J , Dickerson G. D , Sullivan M. S 
Published: June 2018

SummaryA reproducible method is described for quantitating either spontaneous or ADP- induced platelet aggregation in circulating dog blood after heparinization. An extra- corporeal shunt containing screen material with openings 53 microns square was placed in the dog’s arterial circulation. The blood pressure was measured proximal to this filter. The blood pressure decreased upon opening the shunt to the circulation and increased when the filter became occluded. The degree and rate of aggregation was determined by means of measuring these blood pressure changes. Phase and electron microscopy demonstrated platelet aggregates occluding the filters. Platelet aggregation on the filter was experimentally accelerated by infusing ADP before the filter. The administration of ADP in concentrations between 0.625 and 10 μg/ml until occlusion, produced a dose response relationship between log of ADP concentration and rate of filter occlusion. Macrodex, a known inhibitor of platelet aggregation was given intravenously and was found to delay filter occlusion. Similar results were obtained with high intravenous doses of phenylbutazone. The method was used to compare the drug effects with their in vitro effects measured photometrically. It would appear that this technique can be used for demonstrating and quantitating the effects of drugs on the process of platelet adhesion and aggregation in vivo.
Amidase Activity of Urokinase I. Hydrolysis of a-N-Acetyl-L-Lysine p-Nitroanilide
Authors: Petkov D , Christova E , Karadjova M 
Published: June 2018

Summaryα-N-acetyl-L-lysine p-nitroanilide (ALNA) was synthesized as a low-molecular weight model of the natural urokinase substrate plasminogen. Urokinase was found to catalyse anilide bond cleavage. The extent of hydrolysis can be followed spectro- photometrically by using the strong absorption band of one of the products p-nitro- aniline. An accurate, continuous and convenient assay for urokinase is proposed. As determined by the kinetic study, Vmax5 a measure for the sensitivity of an assay, is about 8 times higher than that obtained for the most sensitive urokinase ester substrates. This was demonstrated by its use for tracing the elution of urokinase during the purification of the enzyme by column chromatography.The high apparant Km value obtained is discussed in terms of the mechanism of serine proteinase action on esters and amides.
The Local Sanarelli-Shwartzman Phenomenon in Rats Induced by Human Leukaemic Cells
Authors: Lisiewicz J , Pituch A , Litwin J. A 
Published: June 2018

SummaryThe local Sanarelli-Shwartzman phenomenon (SSP-L) in the skin of 30 rats was induced by an intr a cutaneous sensitizing injection of leukaemic leucocytes isolated from the peripheral blood of patients with chronic lymphocytic leukaemia (CLL), acute myeloblastic leukaemia (AL) and chronic granulocytic leukaemia (CGL) and challenged by an intravenous injection of 100(μ of E. coli endotoxin. SSP-L was observed in 7 rats after injection of CLL lymphocytes and in 6 and 2 rats after AL myeloblasts and the CGL granulocytes, respectively. The lesions in the skin after AL myeloblasts appeared in a shorter time and were of longer duration compared with those observed after CLL lymphocytes and CGL granulocytes. Histologically, the lesions consisted of areas of destruction in the superficial layers of the skin ; the demarcation line showed the presence of neutrophils, macrophages and erythrocytes. Haemorrhages and fibrin deposits near the demarcation line were larger after injection of CLL lymphocytes and AL myeloblasts than after CGL granulocytes. The possible role of leucocyte procoagulative substances in the differences observed have been discussed.
Platelet Fc Receptor as a Mechanism for Ag-Ab Complex-induced Platelet Injury
Authors: Israels E.D , Nisli G , Paraskevas F , Israels L.G 
Published: June 2018

SummaryAntigen-antibody complexes immunologically unrelated to platelet antigens may produce thrombocytopenia in vivo and platelet aggregation and release in vitro. An in vitro platelet system (rabbit and human) was used to study the platelet receptor that mediates the attachment of the immune complex. Platelet aggregation induced by 7 S immune complexes or aggregated gammaglobulin was blocked by prior exposure of the platelet to isolated antibody Fc. Fab from the same antibody was not inhibitory. 5S complexes lacking the Fc piece did not produce aggregation. Serum, as a source of complement was included in the rabbit platelet test system. However, the role of complement is thought to be secondary as it did not bind to platelets in the absence of 7 S complexes and was fixed only secondarily to 7 S binding. On the basis of these studies it is suggested that the platelet membrane contains an Fc receptor and that the primary fixing of immune complexes to the platelet is through the antibody Fc rather than by complement mediated non-specific immune adherence. Antibody Fc fixation to the Fc receptor site of the platelet is probably the common pathway for platelet injury induced by a number of antigen-antibody complexes immunologically unrelated to the platelet.
Influence of Pregnancy and Oral Contraceptives on Platelets in Relation to Coagulation ancl Aggregation
Authors: Lecompte F , Renaud S 
Published: June 2018

SummaryHoltzman rats, 16 to 19 days pregnant, exhibited in vitro hypercoagulability with a 27 % reduction in the plasma clotting time (PCT) (siliconized and plastic) as compared to non-pregnant controls. This hypercoagulability was entirely due to an increased activity of platelet factor 3, since a comparable reduction in the clotting time was obtained when the washed platelets from these animals were resuspended in a standard platelet-poor plasma. In contrast to this, when the platelets in the original plasma were replaced by a phospholipid suspension, the clotting time in plastic but not in glass, was prolonged in pregnant rats, suggesting a decreased activity of the contact system. In addition, the pregnant rats exhibited a marked increased susceptibility of platelets to thrombin and to ADP-induced aggregation.In 6 pregnant women and in 9 women taking contraceptives, a highly significant in vitro hypercoagulability was also present, since the PCT was decreased 26% and 22%, respectively, as compared to the 14 controls. This hypercoagulability appeared to be entirely due to the increased activity of platelet factor 3 as in rat. However, the clear-cut increased susceptibility of platelets to thrombin and ADP-induced aggregation noted in the pregnant rats was not obtained in either the pregnant women or in the women taking contraceptives.
The Effect of Fibrinogen Degradation Products on Plasmin Activity
Authors: Myśliwiec M , Arnesen H , Godal H. C 
Published: June 2018

SummaryPurified fibrinogen degradation products Y, D or E were not found to exert antiplasmin activity as measured by the clot lysis time.Spontaneous inactivation of plasmin was observed during incubation at 37° C. This inactivation was partly prevented by the presence of fibrinogen degradation products, as well as by other proteins.
Decreased Fibrinolysis in Behçet’s Disease
Authors: Chajek Tova , Aronowski Eta , Izak G 
Published: June 2018

SummaryThe coagulation and fibrinolytic systems have been investigated in nine patients suffering from Behçet’s disease. Six of these had thrombophlebitis.The results of these studies revealed markedly elevated fibrinogen concentration and increased factor VIII activity as well as a pronounced decrease in the spontaneous fibrinolytic activity. This latter finding may have resulted from the presence of a potent antiplasmin activity and that of an inhibitor of the plasminogen activator detected in these patients’ sera.It is suggested that decreased fibrinolysis aggravates the thrombotic episodes frequently encountered in Behçet’s disease; accordingly treatment with fibrinolytic agents was found to offer marked benefits.
The Specificity of Antibodies to Factor VIII Produced in the Rabbit after Immunization with Human Cryoprecipitate
Authors: Kernoff P. B. A , Rizza C. R 
Published: June 2018

SummaryThe relationship between the activity-neutralizing and precipitating activities of rabbit antibody to human factor VIII was studied by measuring the changes in levels of the two activities in two sensitized rabbits after stimulation with cryoprecipitates prepared from the plasmas of normal subjects, haemophiliacs and patients with von Wil- lebrand’s disease. Injection of cryoprecipitates prepared from plasmas with a detectable level of factor VIII clotting activity was followed by a marked rise in the level of activity-neutralizing antibody, whereas there was no rise or a continued fall in level after injection of cryoprecipitates prepared from haemophilic plasmas without detectable factor VIII activity. The level of precipitating antibody rose markedly after injection of normal and haemophilic cryoprecipitates, but little or not at all after cryoprecipitates prepared from the plasma of the patients with von Willebrand’s disease. It is suggested that the specific antigenic sites associated with factor VIII clotting activity were not present in cryoprecipitates prepared from haemophilic plasmas without detectable factor VIII activity, and also that antibodies of two different specificities could be detected.
Retention of Platelets by Glass Beads Variation with the Age of the Individual
Authors: Bucher U , Robert Y , Riedwyl H 
Published: June 2018

SummaryPlatelet function has been evaluated by Hellem’s original method in carefully screened normal persons of various ages. Factors which could possibly influence platelet behaviour, such as drugs, smoking, hypercholesteremia, prediabetes, hypertension or uremia were excluded in preliminary examinations. Only individuals in perfect health without a history of coronary heart disease, peripheral vascular disease or other thrombotic disorders were selected. Physical activity did correspond to the age. Variation in results possibly due to technical factors were eliminated by using strictly the same method and material throughout the study and by performing the tests within a relatively short period of time. From an original group of 109 normal persons, 70 individuals between the ages of 10 and 90, who corresponded to the described standards were chosen for further trials. They were divided into 7 age groups, each including 10 individuals within a decade (the last group ranging from 70 to 90 years). Retention of platelets in a column of glass beads was measured by Hellem5s method. The results, expressed as per cent retention and represented graphically, form a parabolic curve with its minimum at the age of 35 (mean ± 2 SD = 50 i 22%). The mathematical function of the curve can be expressed in a formula as second degree polynomial. It is shown by analysis of variance that age is the only factor on which the slope of the curve depends. Physiological or pathological implications of these findings are not known. The results, however, show that age must be taken into account when differences of platelet behaviour are discussed.
Abortion in Cases of Zika Virus Congenital Infection
Authors: Mota Vivian Maria Ribeiro , Cavalcanti Luciano Pamplona de Góes , Delfino Alanna dos Santos , Lopes Thayse Elaine Costa Figueiredo , Pessoa André Luiz Santos , Ribeiro Erlane Marques 
Published: June 2018

AbstractThe emergency in international public health caused by the Zika virus gave rise to the discussion about abortion in cases of congenital Zika virus syndrome (CZS). Therefore, we propose to carry out a bibliographic review on abortion in these cases. Five databases were searched using the following terms: abortion, miscarriage, and zika, with the interposition of the Boolean operator “AND.” In the selected literature, we found references to the lack of information concerning the risks and severity of CZS, to the great psychological distress suffered by pregnant women, and to the risk of unsafe abortions as a justification for abortion in cases of CZS. However, it is necessary to have available tests that could diagnose, in the first trimester of pregnancy, that the fetus has been affected by the virus, and that it may have important limitations, in order to subsidize the qualified discussion about abortion in these cases.
The Action of Vipera aspis Venom on Blood Clotting Factors and Platelets
Authors: Boffa M. C , Josso F , Boffa G. A 
Published: June 2018

SummaryOn human plasma, the venom of Vipera aspis has both an immediate procoagulant effect and a late fibrinogenolytic and fibrinolytic activity. This procoagulant effect is shown in presence of calcium ions and is observed even in the absence of phospholipids. Factors V and X are the main substrates necessary for this action.The venom progressively hydrolyses fibrinogen impairing clot formation. It has a fibrinolytic action in the absence of plasminogen.On platelets, the venom of Vipera aspis inhibits the aggregation induced by ADP, collagen or small amounts of adrenalin. Platelet phospholipids are hydrolysed by the venom and the hydrolysis products are hemolytic. With venom, platelets lose part of their procoagulant properties. The clot formation of PRP is impaired in the presence of the venom as seen on thromboelastogram.
Studies on the Role of Fibrinolysis and Fibrinogen Degradation Products (FDP) in Analgesic Action of Morphine
Authors: Buczko Włodzimierz , Wiśniewski Konstanty 
Published: June 2018

SummaryThe role of fibrinolysis and FDP in the analgesic action of morphine in mice and rats was studied. It was shown that during activation of blood fibrinolysis, both the accumulation of morphine in the brain tissue of rats and the clinical effect of this drug were increased. Similar results were observed after morphine given simultaneously with FDP obtained in vitro. The data from the analysis of FDP carried out on Sephadex G-25 Fine columns suggest that only FDP of molecular weight of about 10,000 potentiate the action of morphine; smaller peptides decreased the action of this drug.
The Effect of Venous Occlusion on the Sequestration of Blood Platelets
Authors: Hladovec J , Koleilat Z , Přerovský I 
Published: June 2018

SummaryThe venous occlusion of all four legs in rats caused a highly significant decrease of platelet counts in venous blood especially after the correction for an opposite change in haematocrit. A very pronounced decrease in platelets was observed in human volunteers after a venostasis in one arm in the blood drawn from the occluded limb just before the release of occlusion. Similar decreases were found after a venostasis of both legs in postocclusion blood samples. The decrease in blood platelets results from temporary sequestration in the occluded limbs. The decreases of platelets after a 10 min occlusion of both legs are more pronounced in patients with post thrombotic states.
Effect of Detergents on Platelet Electrophoresis and Aggregation, and the Possible Relation of Plasma Surface Activity to Thrombosis
Authors: Hampton J. P , Nicholls D. G 
Published: June 2018

SummaryA variety of anionic, cationic, and non-ionic detergent compounds has been shown to increase the sensitivity of the electrophoretic response of human platelets to adenosine diphosphate. The effect of such compounds on normal platelets is very similar to that of plasma from patients with arterial disease, and it is suggested that there may be an abnormality in the surface-active properties of the plasma from such patients. One detergent, cetyl pyridinium chloride, was found not to induce any change in platelet electrophoretic behaviour, but to protect platelets from other detergents. It was also shown to be a powerful inhibitor of platelet aggregation.
Evidence for Two Separate Effects of Adenosine Diphosphate on Human Platelets
Authors: Hampton J. R , Nicholls D. G , Mitchell J. R. A 
Published: June 2018

SummaryFurther studies are reported on the mechanism by which platelets from patients with arterial disease develop abnormal electrophoretic sensitivity to adenosine diphosphate (ADP). Plasma from such patients can only induce abnormal platelet sensitivity to ADP if ADP is itself present. There are two separate effects of ADP on human platelets, one which allows platelets to interact with abnormal plasma, and another which is reflected by changes in platelet electrophoretic mobility ; the former is inhibited by cyanide, and the latter is not.The effects of lecithin on normal platelets are similar to those of abnormal plasma, but if lecithin is incubated with plasma before addition to platelets its effect is lost.
Carbohydrate Structure in Factor VIII
Authors: Austen D. E. G , Bidwell Ethel 
Published: June 2018

SummaryThe work described in this paper provides new evidence that factor VIII is a glycoprotein, based upon a study of inactivation of the factor using extracts of Trichomonas foetus. Such extracts contain powerful enzymes which, it is shown, will destroy factor VIII activity. Furthermore, this destruction can be inhibited by glycoproteins or by certain sugars and when these reactions are examined it is possible to show that the action of T. foetus extracts upon factor VIII is one of glycolysis and hence that factor VIII is a glycoprotein. No similarity is found between the carbohydrate structure in factor VIII and that in blood group substances. In addition, no parallel has yet been found between the reaction of factor VIII with T. foetus extracts and the reaction of factor VIII with its antibody.