bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Uptake of Adenine by Isolated Human Platelet Membranes
Authors: French Paul C. , Sixma Jan J. , Holmsen Holm 
Published: June 2018

SummaryAdenine uptake into isolated platelet membranes had about the same Km (151 ± 21 • 9 nM) as uptake into intact cells (159 ± 21 nM) and was also competitively inhibited by papaverine and hypoxanthine. No uptake occurred at 0° and accumulated adenine was converted to AMP. AMP was not firmly bound to protein as judged by chromatography of triton X-100 solubilized membranes on Sephadex G25. The pH optimum for adenine uptake was at pH 5-5. Exogenous 5-phosphoribosyl-l-pyrophos- phate strongly stimulated uptake. These data may be explained by uptake of adenine by facilitated diffusion followed by conversion to AMP by adenine phosphoribosyltransferase but group translocation cannot be entirely excluded.
Reliability of Laboratory Tests for the Control of Oral Anticoagulation
Authors: Loeliger E. A , Boekhout-Mussert M. J , van Halem-Visser L. P , Habbema J. D. E , de Jonge H 
Published: June 2018

SummaryThe present study concerned the reproducibility of the so-called prothrombin time as assessed with a series of more commonly used modifications of the Quick’s onestage assay procedure, i.e. the British comparative reagent, homemade human brain thromboplastin, Simplastin, Simplastin A, and Thrombotest. All five procedures were tested manually on pooled lyophilized normal and patients’ plasmas. In addition, Simplastin A and Thrombotest were investigated semiautomatically on individual freshly prepared patients’ plasmas. From the results obtained, the following conclusions may be drawn :The reproducibility of results obtained with manual reading on lyophilized plasmas is satisfactory for all five test procedures. For Simplastin, the reproducibility of values in the range of insufficient anticoagulation is relatively low due to the low discrimination power of the test procedure in the near-normal range (so-called low sensitivity of rabbit brain thromboplastins). The reproducibility of Thrombotest excels as a consequence of its particularly easily discerned coagulation endpoint.The reproducibility of Thrombotest, when tested on freshly prepared plasmas using Schnitger’s semiautomatic coagulometer (a fibrinometer-liJce apparatus), is no longer superior to that of Simplastin A.The constant of proportionality between the coagulation times formed with Simplastin A and Thrombotest was estimated at 0.64.Reconstituted Thrombotest is stable for 24 hours when stored at 4° C, whereas reconstituted Simplastin A is not.The Simplastin A method and Thrombotest seem to be equally sensitive to “activation” of blood coagulation upon storage.
Evidence that Human Platelet Aggregating Activity in Porcine Plasma is a Property of von Willebrand Factor
Authors: de Gaetano G , Donati M. B , Vermylen J 
Published: June 2018

SummaryPlasma from normal pigs, but not from a pig affected with von Willebrand’s disease, aggregates human platelets. The aggregating activity therefore seems to be a property of porcine von Willebrand factor.
Cofactor of the “Lupus Anticoagulant”
Authors: Rivard Georges E. , Schiffman Sandra , Rapaport Samuel I. 
Published: June 2018

SummaryNormal plasma contains an activity known as cofactor which further lengthens the clotting time of the plasma of some patients with the “lupus anticoagulant.55 Cofactor has been characterized as either prothrombin or a gamma globulin. Our findings indicate that cofactor has the following properties: stable at room temperature but largely destroyed by heating for 30 min at 56° C; sparingly adsorbed by Al(OH)3 or BaS04; apparent molecular weight on gel filtration around 200,000 daltons ; precipit- able between 50-75% ammonium sulfate saturation. Cofactor was present in plasmas from patients with hereditary deficiencies of factor II, V, VII, VIII, IX, X, XI, XII, or Fletcher factor; however, less cofactor activity was demonstrable in plasmas deficient in factor II, V, or X than in normal plasma or the other deficiency plasmas. Plasma from patients receiving oral anticoagulant therapy had variable levels of cofactor activity which could not be correlated with levels of factor II, VII, IX, X, or staphylocoagulase-reacting factor. Cofactor activity was unaffected by treatment with an anti-human immunoglobulin antiserum. These data support the conclusion that the cofactor reacting with our patient’s “lupus anticoagulant55 is neither prothrombin nor an immunoglobulin, but rather a unique molecule with some properties in common with each.
Fibrinogen Valencia A New Case of Congenital Dysfibrinogenemia
Authors: Aznar J , Fernandez-Pavón A , Regañóon E , Vila V , Orellana F 
Published: June 2018

SummaryA new case of dysfibrinogenemia is described, the proband had low fibrinogen level and a moderate hyperfibrinolysis. Attention is drawn to the florid hemorrhagic picture and its early presentation.The family history showed a moderate hyperfibrinolysis.It appeared that the cause of the dysfibrinogenemia was due to a deficient polymerization of the α chains of the fibrinogen.It is not yet known if this is caused by a defective liberation of fibrinopeptides. Due to the peculiar characteristic of this case and in accordance with the international norms, we propose to call this dysfibrinogenemia “Fibrinogen Valencia.”
Effects of Thrombolytic Therapy on Hemorrhage from Post-operative Wounds
Authors: Cade J. F , Basu D , Muckle T. J , Hirsh J 
Published: June 2018

SummaryHemorrhage from post-operative wounds in different organs and structures during thrombolytic therapy was investigated in relation to the time after surgical trauma and to the results of laboratory tests of coagulation and fibrinolysis. Streptokinase was given to rabbits at different times following the production of standardized wounds in different organs. Bleeding was frequent and severe when streptokinase was given between one and five days after surgery and was most marked from artery, followed in order by kidney, vein, liver, muscle, gut and skin. Bleeding appeared to be associated with the in vitro demonstration of an active systemic fibrinolytic state together with elevated levels of fibrin degradation products.
An Antiproteolytic and Antifibrinolytic Preparation Obtained from the Potato by Means of Chromatography on SE-Sephadex C-50
Authors: Worowski K 
Published: June 2018

SummaryA crude preparation of a proteolytic enzyme inhibitor from potatoes was purified by means of column chromatography with SE-Sephadex C-50 using a stepwise gradient of concentration and pH when eluting proteins from the column. The inhibitor preparation thus obtained is stable for a 28 day period of storage and resistant to the action of various physical and chemical factors harmful to the spatial structure of proteins. The potato protease inhibitor markedly inhibits the activity of trypsin, chymotrypsin, plasmin and alkaline proteases from Aspergillus flavus. The inhibition of pronase and a mixture of acid cellular proteases by this inhibitor is considerably less. Pepsin, cathepsin D, and collagenase are not affected by this inhibitor. The potato inhibitor has a marked inhibitory effect on plasmin fibrinolytic activity both in purified systems and in the plasma euglobulin fraction. It also protects the fibrinogen from the action of this enzyme. It does not, however, inhibit plasminogen activation under the influence of either streptokinase or urokinase.
Chromatographie and Electrophoretic Properties of Synthetic Human Fibrinopeptides
Authors: McKenzie Robin , Pepper D. S , Kay A. B 
Published: June 2018

SummarySome properties of synthetic human fibrinopeptides were studied by thin-layer chromatography, thin-layer electrophoresis and low voltage and high voltage paper electrophoresis. The Rf values and electrophoretic mobilities of the peptides in these systems were determined. In high voltage electrophoresis synthetic and natural (fibrinogen-derived) peptides migrated in an identical fashion.When gel filtration was performed in 0.05 M pyridine or 0.1 N ammonia, synthetic fibrinopeptides A and B appeared to be aggregated. In contrast, when filtration was performed in 1.3 M formic acid, the peptides eluted in positions corresponding to their monomeric molecular weights.In addition it was possible to quantitate synthetic fibrinopeptides by two colorimetric assays, the Sakaguchi reaction and the Folin-Ciocalteu method. Ultraviolet extinction coefficients for each peptide were also determined.
Effects of Nutritional, Endocrine and Metabolic State on the Development of Intravascular Coagulation Induced by Human Serum Preparations with Procoagulant Activity
Authors: Antoniades Harry N. , Iatridis Panayotis G. , Westmoreland Nelson , Simon James D. , Hayes Kenneth C. , Surgenor Douglas MacN. 
Published: June 2018

SummaryInjection of human serum fractions with procoagulant activity into intact rats initiated hypercoagulability, thrombosis and hemorrhage. These in vivo effects were dependent upon the nutritional, endocrine and metabolic state of the animals. Injection in fed rats produced only transient hypercoagulability. In rats fasted 48 hours, the initial hypercoagulability was followed by prolonged hypocoagulation, a decline in blood platelet count, thrombosis and hemorrhage. These effects were reversed in fasted rats by glucose injected 1 hour before the serum fractions. Alloxan-diabetic fed rats and genetically obese fed rats also exhibited enhanced susceptibility to intravascular coagulation on injection of the serum fraction. However, injection of insulin in the diabetic rats before the serum fractions greatly reduced the susceptibility of these animals. The serum fractions used in these studies exhibited potent factor XIIa-like activity in vitro. The present studies demonstrate that the in vivo clotting process can be greatly influenced by the nutritional, endocrine, and metabolic state of the animal and they provide a basis for the investigation of the factors involved.
Quantitation of Fibrin Deposition and Elimination in Organs of Rats Injected with Labelled Fibrinogen and Albumin
Authors: Busch Christer , Rammer Lennart , Saldeen Tom 
Published: June 2018

SummaryA method for quantitation of fiprin deposits in organs of rats, using labelled fibrinogen and albumin, is described. In rats previously injected with 125I-fibrinogen, thrombin was used to induce intravascular deposition of fibrin in various organs. 131I-albumin was injected shortly before sacrifice for determination of the organ plasma volume. The fibrin content of the organ was calculated by subtraction of the plasma and extravascular 125I-radioactivities from the total 125I-content of the organ. The organ plasma radioactivity was obtained as the product of 12 5I in plasma and the organ plasma volume and the extravascular radioactivity as the difference between total and plasma radioactivity in organs of rats before the thrombin infusion. It was found that the method is especially suited for quantitation of fibrin deposition and elimination in the lungs, but it should be also applicable to other organs. In the liver and kidneys certain problems occur which interfere especially with fibrin elimination studies in these organs.
Fibrin-I Degradation Products with a Molecular Weight Higher than That of Fibrinogen
Authors: von Hugo René , Graeff Henner 
Published: June 2018

SummaryThe observation of intravascular lysis of fibrin deposits and of fibrinogen derivatives with a molecular weight higher than the parent molecule in human cases of disseminated intravascular coagulation (DIC) initiated the following in vitro study. Following streptokinase induced plasma clot solubilization fibrinogen derivatives were investigated after ß-alanine precipitation of the plasma samples by polyacrylamide (PAA) gel electrophoresis, intra gel immunoprecipitation, two dimensional gel electrophoresis and by agarose gel filtration. Three fibrin-i degradation products were observed and characterized according to their relative electrophoretic mobility in 5% PAA gel: 0.23, 0.35, 0.46 (fibrinogen: 0.43) x 10-5 cm2/V x sec. They could also be demonstrated after electrophoresis in the presence of 5 M urea. Agarose gel filtration yielded one peak at 180 ml of effluent volume. The 0.23 derivative was eluted in the peak fractions, whilst the 0.35 and 0.46 derivatives were eluted together at approximately 201 ml of the effluent volume (fibrinogen: 225 ml). This indicates, that the three fibrin-i degradation products described are molecular entities with molecular weights higher than fibrinogen and, that the 0.46 derivative has an increased charge/molecular size ratio in comparison with fibrinogen. Corresponding data were obtained by two dimensional gel electrophoresis in gels of different pore size.
A Fibrinolytic Agent from a Saturnid Caterpillar Partial Purification and Characterization
Authors: Arocha-Pinango C. L , Marsh N. A , Robinson D 
Published: June 2018

SummaryPurification and characterization studies were performed on a proteolytic agent obtained from a Saturnid moth caterpillar. Starting material possessed caseinolytic, fibrinolytic and plasminogen-activator activities. The fibrinolytic activity was stable over a wide range of pH and temperature. Purification was performed by molecular exclusion chromatography and ion exchange chromatography. A pH- and heat-stable material was obtained having a molecular weight in the range of 16,000-18,000. This material did not possess the ability to activate human plasminogen but retained direct caseinolytic and fibrinolytic activities. It had no effect on thrombin- and arvin- clotting times of human plasma, on partial thromboplastin time or on the whole blood thrombin generation test. Electrophoresis on cellulose acetate agar gel and polyacrylamide showed the material to be very basic and moving away from any detectable protein. The isoelectric point was found to be greater than pH 10. The relationship between the characterized material and the clinical syndrome caused by contact with the caterpillar remains to be determined.
Scanning Electron Microscopic Observation of Platelets in Hemostasis
Authors: Shimamoto Tatsuo , Yamazaki Hiroh , Shimamoto Takio 
Published: June 2018

SummaryTo observe the very early changes in platelets during hemostasis, exposed carotid arteries of 3 rabbits were punctured with a needle, immediately fixed by 0.5% glutaraldehyde solution and their inner surface examined with a scanning electron microscope (SEM). Many platelets adhered in each case to the inner surface of the artery around the wound and all of them, whether solitary or aggregated, showed a spheroidal form with several pseudopodia.Platelets in shed blood from the incised ear vein of 3 control and 3 heparinized rabbits were fixed by glutaraldehyde and observed by SEM. The percentage of aggregated platelets was 60.9% in the control and 84.1 % in the heparinized rabbits immediately after the incision. The difference was statistically significant (P < 0.01). Sixty seconds after the incision, the percentages of aggregated platelets in the samples from the control and heparinized rabbits were 78.8% and 62.2% respectively. The difference was significant (P < 0.01). In accordance with this phenomenon, the percentage of the number of flat platelets decreased and that of altered platelets increased in the control rabbits. In the heparinized rabbits, far fewer flat platelets and larger numbers of altered platelets were observed in the samples than in those of the control rabbits immediately after the bleeding. However, 15 or 30 seconds later, the platelets of the heparinized rabbits showed fewer changes than those of the control.
Effect of Temperature on ADP-Induced Platelet Aggregation
Authors: Praga C. A , Pogliani E. M 
Published: June 2018

SummaryTemperature represents a very important variable in ADP-induced platelet aggregation.When low doses of ADP ( < 1 (μM) are used to induce platelet aggregation, the length of the incubation period of PRP in the cuvette holder of the aggregometer, thermostatted at 37° C, is very critical. Samples of the same PRP previously kept at room temperature, were incubated for increasing periods of time in the cuvette of the aggregometer before adding ADP, and a significant decrease of aggregation, proportional to the length of incubation, was observed. Stirring of the PRP during the incubation period made these changes more evident.To measure the exact temperature of the PRP during incubation in the aggre- gometer, a thermocouple device was used. While the temperature of the cuvette holder was stable at 37° C, the PRP temperature itself increased exponentially, taking about ten minutes from the beginning of the incubation to reach the value of 37° C. The above results have a practical significance in the reproducibility of the platelet aggregation test in vitro and acquire particular value when the effect of inhibitors of ADP induced platelet aggregation is studied.Experiments carried out with three anti-aggregating agents (acetyl salicyclic acid, dipyridamole and metergoline) have shown that the incubation conditions which influence both the effect of the drugs on platelets and the ADP breakdown in plasma must be strictly controlled.
Immunoreactive Factor VIII in Carriers of Hemophilia A+ and A-
Authors: Lechner K 
Published: June 2018

SummaryFactor VIII activity and inhibitor-neutralizing capacity of plasmas of 30 probable or definite carriers of hemophilia A were compared. The inhibitor-neutralization test is less useful to recognize the carrier-state than the factor VIII assay. Plasmas of two carriers belonging to families (in which, in at least one member, the diagnosis of hemophilia A+ was established) had an inhibitor neutralizing capacity twice as high as expected from the biological activity, while 28 carriers from hemophilia A- families had an inhibitor neutralizing-capacity equivalent to their factor VIII activity.
Studies on the Prolonged Prothrombin Time in Haemophilia BM
Authors: Elödi Susan 
Published: June 2018

SummaryProlonged prothrombin time was measured in four haemophilia B patients with the aid of bovine or rat thromboplastins, whereas normal values were obtained when human or rabbit thromboplastin was used. The anomaly can be ascribed to the decreased level of factor VII. Four carrier relatives exhibited normal prothrombin time independent of the source of thromboplastin. The prolonged prothrombin time appears to be a non-hereditary phenomenon and it may be attributed to a species- specific interaction between thromboplastin of diverse sources and human factor VII, rather than to anomalous factor IX.
Studies on the Mechanism of Action of Synthetic Antifibrinolytics
Authors: Landmann H 
Published: June 2018

SummaryWhen compared with derivatives of benzamidine, the synthetic antifibrinolytics EACA, PAMBA, and trans-AMCHA are weak competitive inhibitors of ester hydrolysis by urokinase, of plasminogen activation by urokinase and streptokinase, and of plasmin action on synthetic substrates, casein, and fibrinogen. In contrast, the inhibitory effect of the antifibrinolytics equal or surpass, that of benzamidine derivatives on the process of fibrin dissolution by plasmin and on plasma clot lysis. Degradation of fibrin monomers by plasmin seems to be equally strongly inhibited by the antifibrinolytics. Thus, fibrin and fibrin monomers are plasmin substrates, the hydrolysis of which is inhibited by the antifibrinolytics in a different way from their other inhibitory effects on plasmin. It is concluded that this activity accounts for the strong action of these inhibitors on the whole process of fibrinolysis.Plasmin, in contrast to other proteolytic enzymes, was shown to possess a specific ability to attack fibrin resulting in rapid formation of soluble products from the insoluble substrate. The strong inhibitory effect of the antifibrinolytics is not caused by their reaction with the substrate, fibrin, but by their blocking the specific interaction of plasmin with fibrin.The molecular mechanism of the plasmin-fibrin reaction and its inhibition is discussed.
Acquired Resistance to Ancrod Its Evaluation and Clinical Occurrence
Authors: Vinazzer H 
Published: June 2018

SummaryA simple test for the detection and quantitation of resistance to ancrod is described. The test is based on the polymerization of fibrinogen by ancrod. The possible variables of the method such as the concentration of fibrinogen, the adsorption of ancrod onto a normal serum protein and the kinetics of the reaction between ancrod and the inactivating substance are examined. By this method, in 4 out of 19 patients who had previously received ancrod, resistance could be detected up to 15 months after therapy. In one of those patients, a second series of doses of ancrod was given. When the dose was elevated to an extent corresponding to the concentration of the inactivating substance, hypofibrinogenemia could be promptly established. The clinical importance of the test is discussed.
Human Fibrinopeptides as Antithrombins
Authors: Gorman J. J , Castaldi P. A 
Published: June 2018

SummaryHuman fibrinopeptides have been isolated from purified human fibrinogen and investigations performed on their reactions with thrombin and platelets. Fibrinopeptides A and B had an inhibitory action against the proteolytic action of thrombin but fibrinopeptide A did not impair the esterolytic activity of the enzyme. Studies on thrombin - catalysed platelet aggregation and C14-Serotonin release showed a similar inhibition but the fibrinopeptides had no effect on platelet reactivity with adenosine diphosphate or collagen. These properties of fibrinopeptides were demonstrated in concentrations compatible with a similar effect in localized thrombosis.
Fibrin Derivatives, Plasma Hemoglobin and Glomerular Fibrin Deposition in Experimental Intravascular Coagulation
Authors: Beller F. K , Theiss W 
Published: June 2018

SummaryPlasma fibrinogen, circulating fibrinmonomers (as indicated by a positive ethanol gelation test), fibrinolysis breakdown products and plasma hemoglobin were assayed in 122 rats subjected to endotoxin injection or infusion. The results were correlated with the quantitative measurement of glomerular fibrin deposition. Based on these data four groups were determined : consumption coagulopathy and three stages of increasing severity of disseminated intravascular coagulation (DIG).Consumption coagulopathy was defined by a decrease in plasma fibrinogen and a positive ethanol gelation test in the absence of glomerular fibrin deposition. Plasma hemoglobin and fibrinolysis breakdown products were normal or only slightly increased.DIG as characterized by glomerular fibrin deposition was defined as moderate (1 to 20% glomeruli showing fibrin strands), intermediate (21 to 80%), and severe (81 to 100%). Decrease in plasma fibrinogen and frequence of a positive ethanol gelation test in all stages of DIG were only slightly different from the findings in consumption coagulopathy. However, a sharp increase in plasma hemoglobin levels was noted when glomerular fibrin deposition did occur even in small amounts. At this time only a moderate increase was noted in fibrin(ogen) breakdown products. These two parameters increased only slightly in the group of intermediate DIG. Severe DIG was characterized by a massive increase in fibrin (ogen) breakdown products and high levels of plasma hemoglobin.