bluuebunny/crossref_metadata_2025 huggingface dataset:
Platelet Function and Plasma Fibrinogen and their Relations to Gender, Smoking Habits, Obesity and Beta-Blocker Treatment in Young Survivors of Myocardial Infarction
Authors: Berglund Ulf , Wallentin Lars , Schenck Henning von
Published: June 2018

Seventy-three (58 men and 15 women) survivors of myocardial infarction below 45 years of age and 73 healthy matched controls were investigated regarding in vitro platelet aggregability to ADP and collagen, platelet sensitivity to prostacyclin and plasma levels of beta-thromboglobulin, platelet factor 4 and fibrinogen. The patients, studied 3-6 months after the acute event, had a reduced platelet sensitivity to prostacyclin. They did not differ from the controls regarding the other platelet function tests. Females had higher platelet reactivity than men. Smoking, obesity or beta- blocker treatment did not influence platelet function. The patients had higher fibrinogen levels than the controls. Gender did not influence, while smoking and obesity increased plasma fibrinogen. Patients on beta-blockade had lower fibrinogen levels than patients without this therapy. The high fibrinogen level and the low platelet sensitivity to prostacyclin might indicate an increased thrombotic liability in young myocardial infarction patients.
4-Hydroxycoumarin Oral Anticoagulants : Pharmacokinetics-Response Relationship
Authors: Thijssen H H W , Hamulyák K , Willigers H
Published: June 2018

The blood coagulating factors II and VII and prothrombin times (Thrombotest) were followed during a dosage interval (= 24 h) in patients on acenocoumarol (n = 6) and on phenprocoumon (n = 6) therapy. The patients were on stable anti-coagulation (%TT: 7-13%) for at least 6 months. The study was performed to investigate the concentration-response relationship of the 4-hydroxycoumarin-type oral anticoagulants. The three parameters were stable during the 24-h interval for patients on phenprocoumon therapy. Patients on acenoumarol showed fluctuations in their factor VII levels; peak activities were observed at about 2 h, trough activities at about 16 h after acenocoumarol intake. Factor II and Thrombotest activities were stable. Plasma levels of phenprocoumon were stable during daytime whereas acenocoumarol levels declined exponentially (t½ about 12 h). The results indicate the oral anticoagulants to exhibit a concentration-response relationship common to drug-receptor interactions. The results also suggest that for stable and long-lasting anticoagulant therapy oral anticoagulants with half-lives beyond the dosage interval (t½>24 h) should be preferred.
Morphometric Analysis of Density Subpopulations of Normal Human Platelets
Authors: Chamberlain K G , Froebel M , Macpherson J , Penington D G
Published: June 2018

Platelets from seven normal subjects were fractionated on continuous Percoll density gradients and low density (LD), intermediate, and high density (HD) platelets were prepared for transmission electron microscopy followed by computerised morphometric analysis. Normal ultrastructural appearance and discoid shape were preserved by incubation of the platelets in nutrient medium at 37 °C immediately before fixation. HD platelet sections had a larger mean cross-sectional area but a lower ratio of the major to the minor axis compared to LD platelet sections. HD platelets contained more alpha granules, dense granules and mitochondria per square micron of section area than LD platelets. The percentage of section area occupied by open canalicular system was greater in the LD platelets while the percentage area occupied by glycogen fields was over ten-fold higher in the HD platelets. The mean cross-sectional areas of individual alpha granules and dense granules increased with density while the opposite trend was found for mitochondria. It is suggested that these ultrastructural differences mainly arise during thrombopoiesis and may indicate some functional specialization among platelets.
Effect of Lupus Anticoagulant on Antithrombogenic Properties of Endothelial Cells - Inhibition of Thrombomodulin-Dependent Protein C Activation
Authors: Cariou Roger , Tobelem Gérard , Bellucci Sylvia , Soria Jeannette , Soria Claudine , Maclouf Jacques , Caen Jacques
Published: June 2018

We have investigated the effect of purified immunoglobulin G (IgG) on endothelial cell functions in 16 patients with lupus anticoagulant, 9 of whom had systemic lupus erythematosus (SLE). Spontaneous or thrombin-stimulated secretion of prostacyclin (PGI2) by cultured human endothelial cells from umbilical cord vein (HUVEC) was not inhibited by the patient’s IgG. Nor was spontaneous release of tissue plasminogen activator (t-PA) or of its inhibitor (PAI) modified in the presence of patient’s IgG.

The rate of activation of purified protein C (PC) by HUVEC in the presence of thrombin was significantly lowered by patient’s IgG or Fab’ fragment (inhibition of 43%). Neutralization of this effect was obtained by incubation of a greater quantity of phospholipids (phosphatidylcholine, phosphatidylserine) with the patient’s IgG. Activation of PC was also performed using purified rabbit thrombomodulin (TM) and a similar inhibition of the patient IgG was observed (inhibition of 48%) but the activation of Gla-domainless PC was not modified.
Aging and Diabetes Increase the Aggregating Potency of Rat Skin Collagen Towards Normal Platelets
Authors: Grigorova-Borsos A M , Bara L , Aberer E , Grochulski A , André J , Mozère G , Peyroux J , Sternberg M
Published: June 2018

Acid-soluble collagen samples were prepared from individual skins of 24 month old rats (n = 8), 2 month old young controls (n = 8) and from 6 month old streptozotocin-diabetic rats (n = 5) and their age-matched controls (n = 10). Less collagen was obtained by acid extraction and salt precipitations from skins of diabetic and aged rats than from those of their respective controls. The collagen preparations from diabetic and aged rats showed an increased ratio of beta/alpha components. The rate of “in vitro” fibrillogenesis was less for collagen from diabetic rats than from controls. It was not modified for collagens from aged rats. The aggregating potency towards normal human platelets was markedly increased for collagens from aged and diabetic rats: reduced latency time (p <0.01) and increased velocity (p <0.01) were observed for collagens from aged rats when compared with young rats (16.5 μg/ml). Increased velocity (p <0.01) was also observed for collagens from diabetic rats (8.25, 11 and 16.5 μg/ ml), without modification of latency time.
A Prospective Study of HIV-Infected Haemophilic Boys and the Prognostic Significance of Immune and Haematological Abnormalities
Authors: Williams M D , Al-Rubei K , Hill F G H
Published: June 2018

Fifty-seven haemophilic boys have been studied prospectively determining T lymphocyte subsets and haematological parameters over a period of 26 months. Clinical follow up of these patients has continued for a further 41 months. At the beginning of the study 21 boys were HIV antibody seropositive and seroconversion was documented in a further 9 during the study period, giving a 52.6% incidence of HIV seropositivity. It has been possible to define a group of patients with persistently falling T4 values and these have shown clinical evidence of HIV infection. Although persistent generalized lymphadenopathy has been observed in 30% of HIV antibody positive boys and some boys have had unexplained fevers, only one boy has progressed to have the acquired immune deficiency syndrome (AIDS) some 5 years and 3 months from HIV seroconversion. This boy had a persistently falling T4 value. The importance of these findings is discussed. To date the abnormalities found in these haemophilic boys irrespective of their age are similar to those already reported in adult haemophiliacs.
Platelet Inhibition in the Management of Thrombosis
Authors: Didisheim Paul , Kazmier Francis J. , Fuster Valentin
Published: June 2018

The role of platelets in the initation of arterial thrombosis is clear. In venous thrombosis as well, platelets may in some circumstances play a significant role.

For these reasons, and because of the complications and limitations of anticoagulant therapy, antithrombotic trials have been launched with several agents which inhibit platelet function.

Regarding postoperative deep vein thrombosis, neither aspirin nor dipyridamole alone appears effective, although the combination offers promise. Results with the dextrans are conflicting. In recurrent idiopathic deep vein thrombosis, sulfinpyrazone may be beneficial.

On the arterial side, transient cerebral ischemic attacks may be favorably affected by either aspirin or sulfinpyrazone. Prevention of thromboembolism associated with prosthetic heart valves appears possible with combination warfarin-dipyridamole therapy, and the beneficial effect of sulfinpyrazone on shortened platelet survival in this group suggests that this agent may also be effective. Sulfinpyrazone may also be beneficial in preventing thrombosis in arteriovenous canulas.

The issue which has attracted the greatest attention and about which no clear answer exists at present is whether antiplatelet agents can modify the course of acute myocardial infarction. Several trials with aspirin are currently underway, and it would be premature to recommend its use in this condition until the results of these trials are available, probably in 1975.
Self-Damping Mechanism in Blood Coagulation
Authors: Nemerson Y , Silverberg S.A , Jesty J
Published: June 2018

Two reactions of the extrinsic pathway of coagulation, the activations of Factor X and prothrombin, have been studied in purified systems and shown to be self-damping. Factor X was activated by the tissue factor - Factor VII complex, and prothrombin by two systems: the coagulant protein of Taipan venom, and the physiological complex of activated Factor X, Factor V, lipid, and calcium ions. In each case the yield of enzyme, activated Factor X or thrombin, is a function of the concentration of activator. These and other observations are considered as a basis for a control mechanism in coagulation.
Fibrinolytic Activity at High Altitude and Sodium Acetate Buffer
Authors: Chohan I. S , Singh I , Balakrihsnan K
Published: June 2018

At high altitude there is a tendency for fibrinolytic activity to be enhanced depending, perhaps, on the duration of exposure and this seems to be a protective mechanism against the development of high altitude pulmonary oedema which is associated with diminished fibrinolytic activity. The fibrinolytic response at high altitude seems to be fluctuated during the process of acclimatisation though being maintained at a plateau higher than that in the plains. It apparently results from hypoxic stress but more likely reflects the physiological response to the hypercoagulable state at high altitude. As clot lysis times in high altitude pulmonary oedema are unusually prolonged an attempt at shortening their observation in the test system is desirable. Sodium acetate, 0.12 M solution with pH 7.4 as a diluent in the low temperature technique of dilute clot lysis time is potentially effective to accelerate the lysis time by approximately 33 % compared to phosphate buffer solution of similar pH and molarity. Also the end point of disintegration of clot is more abrupt and sharply defined. Sodium acetate buffer can advantageously replace phosphate buffer as a diluent in this technique.
Regional Quality Control of Coagulation Assay Procedures (Normotest, Simplastin-A and Thrombotest)
Authors: Kahan Johan
Published: June 2018

The report is based on the first 8 months’ operation of an extended regional quality control program involving 20 hospital laboratories in the Stockholm area. The test material was a commercially available lyophilized human reference plasma containing uniformly reduced levels of factors II, VII and X, and optimal concentrations of fibrinogen and factor V. Each participant received 2 batches of the test material with different activity at each 4-week period. Participants were requested to analyze the specimens, independently and in duplicates, along with ordinary patient samples three times weekly during each period. The levels of the factors in the batches were changed in each period. The total number of reported results was 3113. The statistical analysis of values included the calculation of means and variances within and between different thromboplastins (Normotest, Simplastin-A, Thrombotest), different techniques (venous and capillary blood, automatic and manual end-point determination), and laboratories classified according to the category and number of personnel and of performed coagulation tests. Systematic differences between thromboplastins, techniques and laboratories, even using the same type of thromboplastin, contributed a significantly greater amount than within-laboratory random variation to the total variation of determinations. The obtained results indicate the urgency of the quality control of coagulation activity tests.
Hemostatic Defect due to Acquired Circulating Inhibitors against Lipid Procoagulant and Factor VIII
Authors: Pechet Liberto , Snyder L Michael , Chesney Carolyn , Colman Robert W.
Published: June 2018

An 85 year old woman was studied because of severe bleeding. Acquired inhibitors to factor VIII and to phospholipid procoagulants were demonstrated. Platelet factor 3 (Pf3) assay was prolonged with both kaolin and Russell’s Viper Venom (StypvenE). It was normal with patient’s washed platelets and normal plasma, but abnormal when normal platelets were incubated with patient’s plasma. The inibitor also blocked the coagulant action of Bell and Alton thromboplastin, inosithin, phosphatidyl ethanolamine and phosphatidyl choline, but not that of tissue thromboplastin or cardiolipin. All other platelet functions were normal. The inhibitors were purified by A1 (OH3) absorption, heating at 56°, precipitation by 50% ammonium sulfate, followed by dialysis and DEAE-cellulose chromatography. A partial separation of the two inhibitors was achieved.

Cyclophosphamide treatment resulted in cessation of bleeding and disappearance of the inhibitors. This seems to be the first instance of an acquired circulating inhibitor specifically directed against phospholipid procoagulants in a patient who also had an inhibitor to Factor VIII.
Abnormal Antithrombin III (Antithrombin III ‘Budapest’) as a Cause of a Familial Thrombophilia
Authors: Sas G , Blaskó G , Bánhegyi D , Jákó J , Pálos L. Á
Published: June 2018

A family with a high incidence of spontaneous thromboembolism has been investigated and those members affected were found to have significantly depressed levels of plasma and serum heparin cofactor activity; i.e., antithrombin III and anti-Xa activity. Further studies revealed that despite a marked diminution of antithrombin III activity in these patients measurement of antithrombin III by immunological techniques showed the levels to be normal. It is concluded that this anomaly represents a defect in the synthesis of the antithrombin III molecule. The abnormality appeared to be inherited but the mode of inheritance could not be determined with the available data.
Normal Platelet Aggregating Properties of Ehlers-Danlos Syndrome “Collagen”
Authors: Deliyannis Angelo A. , Kontopoulou-Griva Irene , Tsevrenis Hippocrates V.
Published: June 2018

Normal platelet aggregating activity of collagen taken from a patient with Ehlers-Danlos syndrome is reported.
Thrombin Interaction with Human Platelets Potentiation of Thrombin-induced Aggregation and Release by Inactivated Thrombin
Authors: Phillips David R.
Published: June 2018

The possibility that thrombin acts on platelets by a mechanism other than proteolysis was investigated. The proteolytic site of thrombin was modified with phenylmethylsulfonyl fluoride (PMSF). This modified enzyme did not induce platelet aggregation or the platelet release reaction. Platelets were then incubated with the inactivated enzyme (PMS-thrombin) and later with active thrombin. In this sequence of incubation, PMS-thrombin enhanced not only platelet aggregation induced by active thrombin but also the thrombin-induced release reaction. Preincubation with PMS-thrombin was essential for this enhancement as the inhibited enzyme did not affect aggregation if added after active thrombin. The effect of PMS-thrombin was limited to thrombin-induced reactions of the platelet. The inhibited enzyme had no effect on aggregation induced by adenosine diphosphate or collagen, or on thrombininduced coagulation of fibrinogen. These results suggest (1) that both proteolytic and binding sites for thrombin are present on the human platelet plasma membrane ; and (2) that interaction of thrombin with the binding site potentiates the activity of the proteolytic site.
Concentration Effects of Platelets, Fibrinogen and Thrombin on Platelet Aggregation and Fibrin Clotting
Authors: Chao Francis C. , Tullis James L. , Kenney Dianne M. , Conneely Gail S. , Doyle John R.
Published: June 2018

The effects of varying concentrations of platelets, fibrinogen and thrombin on platelet aggregation and on fibrin clotting were investigated. The results indicated that a threshold thrombin to platelet concentration ratio may be required to cause platelet activation. Above the threshold ratio, platelets exhibited properties which enhanced thrombin action in causing aggregation and fibrin clotting. At T/P ratios below the threshold level, the presence of platelets reduced thrombin activity, in other words, platelets exerted an antithrombin action. Fibrinogen at low concentrations (0.02-1.5 mg/ml) enhanced platelet aggregation induced by thrombin; whereas, at high concentrations of fibrinogen (2.0-4.0 mg/ml), aggregation was markedly inhibited. Continuous mixing of samples of platelets and fibrinogen at physiological concentrations with thrombin at low concentrations ( ˂ 2.0 U/ml) resulted in platelet aggregation. On the other hand, fibrin clots formed in samples without mixing or with high thrombin concentrations (≥ 5.0 U/ml). These results suggested that the quantitative relationships between platelets, fibrinogen and thrombin, and the presence or absence of cell contact may be important factors in determining the overall hemostasis.
Fibrinogen-Fibrin-Related Antigen Pattern in Human Blood
Authors: Jacobsen Carl D. , Hoak John C. , WU Kenneth K. , Fry Glenna L.
Published: June 2018

In serum from patients with DIC at least 3 different FR-antigenic components could be found. It was difficult to demonstrate these components in the corresponding plasma samples. It is possible that a portion of these antigens formed as a result of in vitro clotting despite the presence of proteolytic inhibitors. These results suggest that the interpretation of “increased split products in serum” may be more complex than current concepts indicate.
The Use of the Fibrinogen Turnover and the Isotope Scanning of the Legs for the Diagnosis of Venous Thrombosis in Non Surgical Patients
Authors: den Ottolander G. J. H , van der Maas A. P. C , Schopman W
Published: June 2018

In 2 groups of non surgical patients with venous thrombosis (V. T.) the fibrinogen turnover rate was determined in addition to scanning of the legs.

In the first group of 13 patients with clinical signs of V. T. the Tx/2 of 131I-fibrinogen was shorter than in a normal group. In the second group of 10 patients with V. T., diagnosed only by local scanning of the legs using 125I-fibrinogen, the T72 was also shortened.

Because of the longer half life time of the 125I-label, observations can be carried out during a period of 20 days, so that 125I-fibrinogen is preferable to 131I-fibrinogen. Of 33 elderly patients treated for congestive heart failure a positive leg scan was observed in 15. Treatment with intravenously injected heparin immediately interferes with further accumulation of radioactivity and corrects the shortened TVa to normal values, in contrast to treatment with oral anticoagulants.
Substrate Composition and the Effect of ε-Aminocaproic Acid on Tissue Plasminogen Activator and Urokinase-induced Fibrinolysis
Authors: Thorsen Sixtus , Astrup Tage
Published: June 2018

The influence of variations in substrate composition on the biphasic pattern of inhibition by e-aminocaproic acid (EACA) of urokinase-induced fibrinolysis, first observed on bovine plasminogen-rich fibrin, was studied using a fibrin clot lysis time assay. Different species of fibrinogen and plasminogen or plasmin were used. Preparations of different degrees of purification were compared at varying concentrations. The behavior of urokinase was compared with that of a porcine tissue plasminogen activator. Variations in the conditions of the assay greatly influenced the results. The concentration of fibrinogen had a particularly marked influence. At increased fibrinogen concentrations the biphasic response of urokinase was enhanced and a weak biphasic effect was also produced by the tissue activator which usually yields a uniformly increasing inhibition curve. The phase of fibrinolysis enhancement produced by urokinase with genuine plasminogen substrates occurs at substrate concentrations and EACA levels present in patients treated with EACA. The observed variations may explain discordant findings reported by various investigators.
Storage of Human Blood Platelets
Authors: Hardeman M. R , Heynens Carina J L.
Published: June 2018

Storage experiments were performed at 4°, 25° and 37° C with platelet-rich plasma under sterile conditions. In some experiments also the effect of storing platelets at 4° C in whole blood was investigated.

Before, during and after three days of storage, the platelets were tested at 37° C for their serotonin uptake and response to hypotonic shock. In addition some glycolytic intermediates were determined.

A fair correlation was noticed between the serotonin uptake and hypotonic shock experiments. Both parameters were best maintained at 25° C. Also platelet counting, performed after the storage period, indicated 25° C as the best storage temperature. Determination of glycolytic intermediates did not justify any conclusion regarding the optimal storage temperature. Of the various anticoagulants studied, ACD and heparin gave the best results as to the serotonin uptake and hypotonic shock response, either with fresh or stored platelets. The use of EDTA resulted in the lowest activity, especially after storage.

The results of these storage experiments in vitro, correspond well with those in vivo reported in the literature.
The Inhibition of Platelet Aggregation by an Aorta Intima Extract
Authors: Heyns A. du P , van den Berg D. J , Potgieter G. M , Retief F. P
Published: June 2018

The platelet aggregating activity of extracts of different layers of the arterial wall was compared to that of Achilles tendon. Arterial media and tendon extracts, adjusted to equivalent protein content as an index of concentration, aggregated platelets to the same extent but an arterial intima extract did not aggregate platelets. Platelet aggregation induced by collagen could be inhibited by mixing with intima extract, but only to a maximum of about 80%. Pre-mixing adenosine diphosphate (ADP) with intima extracts diminished the platelet aggregation activity of the ADP. Depending on the relationship between ADP and intima extract concentrations aggregating activity could either be completely inhibited or inhibition abolished. Incubation of ADP with intima extract and subsequent separation of degradation products by paper chromatography, demonstrated a time-dependent breakdown of ADP with AMP, adenosine, inosine and hypoxanthine as metabolic products; ADP removal was complete. Collagen, thrombin and adrenaline aggregate platelets mainly by endogenous ADP of the release reaction. Results of experiments comparing inhibition of aggregation caused by premixing aggregating agent with intima extract, before exposure to platelets, and the sequential addition of first the intima extract and then aggregating agent to platelets, suggest that the inhibitory effect of intima extract results from ADP breakdown. It is suggested that this ADP degradation by intima extract may play a protective role in vivo by limiting the size of platelet aggregates forming at the site of minimal “wear and tear” vascular trauma.
Preferential Disappearance of Aerobically Generated ATP from Platelets during Thrombin-induced Aggregation
Authors: Matsui Satoko , Watanabe Yasuko , Kobayashi Bonro
Published: June 2018

Thrombin-induced nucleotide disappearance from rabbit platelets labelled with 32P under oxidative and glycolytic conditions was observed. After adding thrombin to a platelet suspension previously incubated with 32P in the presence of succinate or of glucose + KCN, radioactive ATP formed under the oxidative condition disappeared rapidly from cells and medium, while that formed under the glycolytic condition remained within aggregates. Since no significant difference was observed between the amounts of ATP generated during thrombin-induced aggregation in both systems, the preservation of radioactive ATP in aggregates under glycolytic conditions cannot be attributed to an increase in ATP generation through glycolysis during aggregation. Rather, it is conceivable that consumption of newly synthesized ATP is markedly stimulated under oxidative conditions. Sonic disruption of labelled platelets followed by subcellular fractionation revealed that ATP generated in both the oxidative and glycolytic systems was found in the soluble fraction of the cells. The possible presence of sub compartments in “the rapidly labelled pool” of ATP in the soluble fraction is discussed.
The Uptake of Adenine by Isolated Human Platelet Membranes
Authors: French Paul C. , Sixma Jan J. , Holmsen Holm
Published: June 2018

Adenine 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

The 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

Plasma 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

Normal 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

A 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

Hemorrhage 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

A 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

Some 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

Injection 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

A 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

The 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

Purification 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

To 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

Temperature 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

Factor 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

Prolonged 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

When 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

A 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

Human 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.