bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Subunits and Transamidase Activity of Factor XIII During Disseminated Intravascular Coagulation in Acute Leukaemia
Authors: Rodeghiero F , Barbui T , Battista R , Chisesi T , Rigoni G , Dini E
Published: July 2018

The "in vivo" thrombin generation which occurs during disseminated intravascular coagulation (DIC) leads to complex coagulation abnormalities. The subunit A of fibrin stabilizing factor (Factor XIII) is a sensitive target for thrombin whilst the subunit S, is not. The two subunits seem to be insensitive to plasmin.

A typical DIC picture has been found in 15 out of 200 cases of acute leukaemia; the subunits and the transamidase activity (TA) of the enzyme were severely reduced. The biologically active component, subunit A, and its TA were found to be much more reduced (P < 0.001) in patients with DIC than in those with AML without typical laboratory DIC pattern ("controls"). The levels of subunit A were correlated only with fibrinogenaemia. No difference in subunit S levels was found between normal healthy subjects and "controls". On the other hand this subunit was significantly reduced in DIC patients.

It is assumed that thrombin affects the zymogen Factor XIII leading to the activation product A2S which could be cleared from the circulation. An alternative explanation of the decrease of subunit S, insensitive to thrombin, could be sought in a defect of its synthesis which seems to be related to that of subunit A, as it has been shown in congenital Factor XIII deficiency.

Haemorrhagic complications are common and often fatal in patients with acute leukaemia. Platelet transfusion therapy has reduced the risk of haemorrhage but there are cases, not responsive to platelets, in whom the haemostatic mechanism is altered, generally by disseminated intravascular coagulation (DIC) (1). This syndrome results from an exaggerated response to cell damage with release of thromboplastic substances which activate "in vivo" the coagulation system. Thus, the "in vivo" thrombin generation leads to a consumption pattern including reduced levels of platelets, fibrinogen, factor V, VIII and XIII; positive paracoagulation tests; prolonged thrombin time and increased fibrin degradation products (FDP). However, patients with haemorrhages, presumably due to DIC, do not always show all of the above laboratory features (2, 3). Moreover, conclusive and extensive clinical studies of the biological expression of the syndrome are missing especially in acute leukaemia. Consequently, the diagnostic criteria for DIC are not yet well established and the diagnostic or prognostic role of a single coagulation factor is not definitively known. Concerning Factor XIII in acute
An International Collaborative Study Establishing a Reference Preparation for Antithrombin III
Authors: Kirkwood T B L , Barroweliffe T W , Thomas D P
Published: July 2018

An international collaborative study involving 12 laboratories in 7 countries was carried out to establish a suitable reference preparation of antithrombin III (At III). The amount of At III present in two purified preparations, a freeze-dried normal plasma and local normal plasma pools was measured by clotting, immunological, and amidolytic assays. 120 assays were submitted of which 105 were accepted as valid for inclusion in subsequent analyses. Less laboratory to laboratory variation was found when At III was assayed in freeze-dried normal plasma, as compared to purified preparations of At III, and there was also less method to method variation when At III was measured in freeze-dried plasma. When measured as heparin co-factor activity, the two purified preparations contained only about half the level of At III found by immunoassay or progressive At III clotting assays. In contrast, the use of freeze-dried plasma provided results which showed excellent agreement between the various laboratories by all assays; accordingly, this material has been established by the World Health Organization as the International Reference Preparation for At III, with an assigned potency of 0.9 i. u. per ml.
Platelet Count on Acute Induction to High Altitude
Authors: Sharma Subhash C
Published: July 2018

Platelet counts in 50 normal healthy volunteers were performed at sea level and then serially on rapid induction to 3658 m by air. Subjects were divided into "symptomatic" and "asymptomatic" groups depending on their score on the symptoms score chart. All were brought back to sea level and study repeated. Platelet count in the symptomatic group showed a falling trend while in the asymptomatics a gradual rise was noted.
The Lysis of Artificial Thrombi
Authors: Metcalf Michael J
Published: July 2018

The susceptibility to lysis of artificial thrombi formed from native rabbit blood in the presence or absence of dextran was determined using the Chandler loop technique. Thrombi of identical weight were formed in the presence of saline or dextran and when spontaneous thrombolysis was allowed to take place, thrombi formed in the presence of dextran 70 were lysed to a greater extent than those formed under control conditions.

The possible factors influencing this observation were studied. Increasing concentrations of streptokinase increased the extent of thrombolysis in both control and dextran treated thrombi. Maximal streptokinase induced thrombolysis occurred in the presence of a 2 per cent final concentration of dextran Mw 40,000 and 500,000 and dextran 70 at a final concentration of 1.2 per cent.

Increased thrombolysis was not observed when albumin was substituted for dextran.

Finally, similar observations were recorded for streptokinase induced thrombolysis using human blood.
Increased Ristocetin-Cofactor in Acute Myocardial Infarction: a Component of the Acute Phase Reaction
Authors: Cucuianu Mircea P , Missits Ileana , Olinic Nour , Roman Stefan
Published: July 2018

When compared to the values obtained in healthy normal-weight, normolipemic controls, the plasma level of ristocetin-cofactor (VIII: R-cof.) was found to be much higher in patients with acute myocardial infarction and in postoperative conditions (4–5 days after a major surgical intervention). A lesser increase of VIII: R-cof. was noted in atherosclerotic patients without acute occlusive accidents and no significant changes of this plasma factor could be observed in hyperlipemic subjects without obvious clinical atherosclerosis. Serial studies emphasized a tendency towards normalization of plasma VIII: R-cof. as the acute phenomena of a myocardial infarction subsided. The above mentioned data suggest that the high levels of VIII: R-cof. recorded in myocardial infarction are mainly caused by a systemic acute phase reaction and to a lesser extent by endothelial damage. Delayed clearance of VIII: R-cof. subsequent to a hepatic dysfunction or to a modified pattern of protein metabolism during the above mentioned acute phase reaction might also contribute to the high level of this plasma factor.
Simplified Thromboplastin Calibration: Further Experience of the Dutch Reference Laboratory for Anticoagulant Control
Authors: Besselaar A M H P van den , Halem-Visser L P van , Hoekstra-Schuman M , Marel-van Nieuwkoop W van der , Loeliger E A
Published: July 2018

The modified (and thereby simplified) thromboplastin calibration procedure using pooled lyophilized normal and patient plasmas is shown to equal, for batch-to-batch control of Thrombotest, the calibration procedure described by Biggs and Denson, which makes use of individual freshly prepared patient plasmas.
Reliability of Amidolytic Assays for Progressive Antithrombin and Heparin Cofactor Activities on Capillary Blood
Authors: Jensen A Hurlet-Birk , Maes E , Gillet C , Legrand-Monsieur A
Published: July 2018

Amidolytic assay of antithrombin III on capillary blood can validly substitute for similar assays performed on venous blood, as an excellent correlation exists (r = 0.95).

For the amidolytic assays of heparin cofactor activity, a much less satisfactory correlation is found (r = 0.81). Results are far more dispersed and a decrease is observed in late capillary samples.

Using a low heparin concentration to assay heparin cofactor activity leads to surprisingly high activities for capillary blood. The same type of discrepancy is observed during the earliest stages of clotting of venous blood.
Abnormal Aggregation and Increased Size of Platelets in Myeloproliferative Disorders
Authors: Cortelazzo Sergio , Barbui Tiziano , Bassan Renato , Dim Enrico
Published: July 2018

Platelet aggregation is frequently impaired in myeloproliferative disorders (MPD). The presence of spontaneous platelet aggregation (SPA) or alterations of the aggregation pattern after ADP, epinephrine and collagen have been a frequent feature in the series of 52 patients here presented. The occurrence of SPA was not related to the findings obtained with the aggregating agents or to the number of circulating platelets. The aggregation results did not correlate with the number of megathrombocytes.

The presence of platelet abnormalities, not completely corrected after busulfan therapy, and the increased size of platelets should aid in diagnosis of myeloproliferative disorders.
Gel Permeation Chromatography of Heparins
Authors: Mulloy Barbara , Johnson Edward A
Published: July 2018

Gel permeation chromatography of heparins using water as solvent has recently been used to obtain fractions for biological investigation. We find that heparin fractions obtained in this way are not, necessarily, differentiated simply on a molecular size basis as has been alleged. Correlations between biological activity and molecular size obtained using such fractions must therefore be treated with caution.
Increased Bleeding during Liver Resection in Ethanol-Intoxicated Rats
Authors: Bengmark Stig , Göransson Göran , Idvall Jan , Zoucas Evita
Published: July 2018

The effect of ethanol intoxication on hemostasis after liver resection was studied in the rat. Plasma levels of ethanol were within the range of those found in ethanol intoxication in man. Bleeding time and blood loss were significantly increased, whereas hemoglobin and hematocrit values were decreased after resection in intoxicated animals compared to controls. APT-times and platelet counts did not differ significantly between the two groups of rats. ADP- and collagen-induced platelet aggregation was slightly inhibited one hour after ethanol administration in non-operated animals. A decrease in pH, such as observed in intoxicated animals, did not affect hemostasis. Distribution of cardiac output was significantly altered after ethanol intoxication. Renal blood flow was increased by 54%, blood flow in the hepatic artery by 40% and in the portal vein by 47%.
Platelet Dense Bodies Loaded with Mepacrine Study in Chronic Idiopathic Thrombocytopenic Purpura (ITP)
Authors: Hourdille P , Bernard P , Reiffers J , Broustet A , Boisseau M R
Published: July 2018

In 22 cases of chronic ITP, the platelet 5-HT storage organelles were counted by examination of platelets loaded with mepacrine and correlated with the size and volume of the platelets. Statistical analysis showed that the mean volume and the number of granules increased in ITP without increase in the mean number of granules per unit volume. A strong correlation was found between platelet long diameter and number of dense bodies in controls (44 healthy subjects) (r = 0.94; y = 2.826 × – 0.699) and in ITP (r = 0.92; y = 2.587 × + 0.06). This study demonstrated in chronic ITP the presence both of platelets without granules and others rich in granules. These anomalies were present no matter what the count of platelets and did not change the mean values for granules and for ADP in most cases. Most platelets remain morphologically normal.
Purification and Partial Characterization of a Hereditary Abnormal Antithrombin III Fraction of a Patient with Recurrent Thrombophlebitis
Authors: Tran T H , Bounameaux H , Bondeli C , Honkanen H , Marbet G A , Duckert F
Published: July 2018

A relatively low heparin cofactor activity (0.60 U/ml) was observed in a patient with recurrent superficial thrombophlebitis of the left leg. However, the antigen concentration was in the normal range (1.04 U/ml) and the progressive antithrombin activity was normal. The crossed immunoelectrophoresis in presence of heparin in agarose gel separated the patient's AT-III antigen in 2 fractions with different mobilities. The patient's AT-III was purified for further characterization. The last step of the purification procedure, a heparin-agarose chromatography, led to a separation and a purification of 2 AT-III fractions with different heparin affinities: an abnormal AT-III with reduced heparin affinity and a normal AT-III with a heparin affinity similar to that of AT-III isolated from normal plasmas. Abnormal and normal AT-III share several identical properties as molecular weight, ability to form complexes with thrombin and progressive antithrombin activity.
Catabolism of Human Fibrinogen Fragment D in Normal Subjects and Patients with Liver Cirrhosis
Authors: Ardaillou Nicole , Yvart Jeannine , Bras Philippe Le , Larrieu Marie-José
Published: July 2018

The catabolism of human fragment D, (FgD), obtained by plasmin digestion of fibrinogen has been investigated in normal subjects and patients with liver cirrhosis and the results compared with those obtained for fibrinogen (Fg). Fg was labelled with I-125 and Fg D with I-131 using the chloramine T method. The plasma disappearance curves of both labelled proteins fitted a two exponential curve. In controls the plasma clearance rate of Fg D was greater than that of Fg as shown by the marked difference between the half-lives of these two tracers: 8,9 and 83,5 hours for Fg D and Fg respectively. The fractional catabolic rate of Fg D was 3.38 times the plasma pool per day. In nine patients with liver cirrhosis, catabolism of Fg was not modified. In contrast, catabolism of Fg D was significantly reduced with a half life of 13.0 hours and a low fractional catabolic rate. These results suggest the role of the liver in the catabolism of Fg D in man.
Optical Density Variations and Microscopic Observations in the Evaluation of Platelet Shape Change and Microaggregate Formation
Authors: Kitek A , Breddin K
Published: July 2018

Addition of Ristocetin to formalin-fixed platelets suspended in diluted PPP induces a marked increase in turbidity which is not caused by platelet shape change but by the formation of microaggregates. If diluted PPP of patients with severe von Willebrand's disease is used, only an initial increase in turbidity and no further decrease is observed without any form variation of the platelets but again with formation of many microaggregates. In normal PRP diluted with buffered EDTA, ADP induces an increase in turbidity without further changes in optical density. Simultaneously platelets immediately change their shape with formation of pseudopodes and sphering but at the same time also microaggregates appear. Shape change and microaggregate formation can also be observed after the addition of Collagen to undiluted PRP which is followed by the formation of large aggregates and a decrease in optical density. Increase in optical density in undiluted PRP is not a specific indicator of platelet shape changes. Microaggregates can alone or partially be responsible for these changes. For the evaluation of platelet shape changes but also for the estimation of microaggregate formation microscopic methods are preferred.
Evidence against Vitamin K Deficiency in Normal Neonates
Authors: Malia R G , Preston F E , Mitchell V E
Published: July 2018

Umbilical cord plasmas from 24 normal full-term neonates were studied. We confirmed the prolonged prothrombin time and low levels of Vitamin K dependent clotting factors previously described (1), but using a number of recently developed immunological and coagulation techniques we could find no evidence of vitamin K deficiency. We conclude that the decreased levels of vitamin K dependent clotting factors of normal neonates are the result of decreased synthesis by the immature liver and that it is questionable whether vitamin K prophylaxis is necessary for these infants.
Anticoagulation by Constant Subcutaneous Heparin Infusion
Authors: Parrilla Nenita , Ansell Jack
Published: July 2018

A preliminary clinical trial was conducted to determine the feasibility of achieving and regulating therapeutic anticoagulation with heparin given by continuous subcutaneous infusion. Five patients with deep venous thrombosis confirmed by impedance plethysmography and/or venography were studied. All patients received an initial heparin dose of 5000 units by IV bolus. This was followed by a continuous subcutaneous heparin infusion at a dose of 15 to 25 units per kilogram per hour. Effective levels of anticoagulation were achieved in all five patients. Regulation and maintenance of therapeutic anticoagulation were no more difficult than with intravenous therapy. No major complications were encountered during therapy.

Continuous subcutaneous infusion of heparin may have advantages over standard intravenous therapy or high dose intermittent subcutaneous therapy. However, more extensive clinical evaluation is warranted.
Preactivation and Deactivation of Blood Platelets
Authors: Aursnes Ivar
Published: July 2018

Human blood anticoagulated with a serine protease inhibitor was centrifuged with an erythrocyte agglutinating agent in the bottom of the tube. Platelet rich plasma (PRP) obtained in this manner contained platelets with different ability to aggregate with ADP located in the various layers of the tube. Platelets in the midportion of the tube were most extensively aggregated by a standard dose of ADP (1.6 μM) and mechanical stirring. Platelets in the lowest portion aggregated least, but still showed normal “shape change” when they were stimulated. The uppermost platelets in the tube also showed somewhat reduced aggregation compared with the midportion. These observations could not be explained by differences in platelet concentrations. On a descriptive basis the platelets in the midportion of the tube are designated preactivated and the lowermost platelets deactivated.
The Role of Platelet Membrane Potential in the Initiation of Platelet Aggregation
Authors: MacIntyre D E , Rink T J
Published: July 2018

The membrane potential of human platelets, and the role of this potential in platelet aggregation, was assessed using the non-covalent, fluorescent probe DiS-C3-5. High K+ and Gramicidin depolarised the cells, whereas valinomycin in standard (4 mMK+) solution produced a hyperpolarisation. Very small changes in potential were observed when choline Cl replaced NaCl. These findings indicate that platelets possess a relatively K+-permselective membrane. The resting potential calculated from the “valinomycin null point” (the K+ concentration gradient at which valinomycin did not change the potential) was approximately – 60 mV. Other factors that contribute to the platelet membrane potential include a significant Cl− permeability, demonstrated by replacing Cl− with methylsulphate, and an electrogenic Na+ pump, demonstrated using strophanthidin. Little or no change in potential was observed upon addition of ADP, collagen, U44069 or thrombin. Neither strong depolarisation with high K+ or gramicidin nor hyperpolarisation with valinomycin induced platelet aggregation or altered platelet responses to agonists. It is concluded that the information transduction mechanisms involved in platelet activation do not include changes in platelet membrane potential.
Protection of Platelet Surface Bound Factors IX a and VIII Against Specific Inhibitors
Authors: Váradi Katalin , Elödi Susan
Published: July 2018

The rate of inactivation of factors IX a and VIII as well as of the complex formed by them on the surface of platelets, induced by specific inhibitors has been studied. After the formation of complex both factors became more protected against high molecular weight inhibitors. As evidenced by the apparent first order inactivation rate constants, after complex formation the velocity of IX a – antithrombin III + heparin reaction fell to one-fourth, that of factor VIII – VIII : C antibody reaction decreased to 1/20. Enhanced resistance toward the high molecular weight inhibitors is presumably due to a steric change, since the low molecular weight phenylmethyl sulfonyl fluoride and diethyl pyrocarbonate inhibited free and complexed factor IX a to the same extent.
Prolongation of Rat Tail Bleeding Time Caused by Oral Doses of a Thromboxane Synthetase Inhibitor Which Have Little Effect on Platelet Aggregation
Authors: Butler K D , Maguire E D , Smith J R , Turnbull A A , Wallis R B , White A M
Published: July 2018

N (7-carboxyheptyl) imidazole is an inhibitor of platelet thromboxane synthetase that has no effect on the cyclooxygenase activity. An oral dose of the substance to rats (10 mg/kg) prolonged tail bleeding time from 170 ± 13 sec to 284 ± 22 sec. This oral dose also inhibited platelet thromboxane B2 production induced by collagen ex vivo but had little effect on the aggregation dose response curve. There was no effect on thrombin-induced aggregation.

Neither the thrombocytopenia induced by the Arthus reaction nor thrombus formation on an implanted cotton thread were inhibited by oral doses of carboxyheptylimidazole up to 30 mg/kg. Similarly neither the prothrombin nor activated partial thromboplastin time were affected.

It is postulated that this thromboxane synthetase inhibitor prolongs bleeding time not by inhibiting platelet aggregation or blood coagulation but rather by preventing the vasoconstriction which would normally be caused by thromboxane A2.
Effects of 8-(N, N-Diethylamino)Octyl 3,4,5-Trimethoxybenzoate HCI (TMB-8) on Washed Blood Platelets with Special Reference to a Specific Loss of Serotonin
Authors: Mürer E H , Siojo E
Published: July 2018

8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate HCl (TMB-8) has been used to indicate involvement of Ca++ in platelet activities, but possible other effects have not been investigated. This study investigates TMB-8-induced leakage of cytoplasmic content and specific loss of one granule constituent, serotonin from washed platelets. TMB-8 concentrations above 0.5 mM block secretion initially and induce leakage after short time incubation. TMB-8 (0.15 mM) enhances a slow release of serotonin, but inhibits a slow release of low affinity platelet factor 4 antigen which take place when washed platelets are incubated at pH 7.4 and 37°C. These effects should be taken into consideration when TMB-8 is used as a calcium antagonist in platelets.
The Effects of Inaccurate Blood Sample Volume on Prothrombin Time (PT) and Activated Partial Thromboplastin Time (aPTT)
Authors: Peterson Powers , Gottfried Eugene L
Published: July 2018

The results of determinations of the prothrombin time (PT) and the activated partial thromboplastin time (aPTT) are frequently used to assess hemostatic function. Accurate results for these laboratory tests depend on many variables, one of which is the ratio of plasma to anticoagulant. We studied 12 patients and 4 normal subjects to determine the effects of sample volume on PT and aPTT. We conclude that underfilling may produce profound effects, particularly on the aPTT. In contrast, overfilling rarely affects the results. The greatest effects of sample volume were observed in specimens in which the true PT or aPTT was elevated. A normal PT or aPTT result on any specimen, regardless of sample volume, strongly suggests that the true value is normal.
A Comparison of Pentosan Polysulphate and Heparin II: Effects of Subcutaneous Injection
Authors: Fischer A-M , Merton R E , Marsh N A , Williams S , Gaffney P J , Barrowcliffe T W , Thomas D P
Published: July 2018

A comparison has been made between the effects of pentosan polysulphate (SP54) and mucosal heparin following subcutaneous injection in man. Unlike heparin, pentosan polysulphate has relatively little effect in vivo as measured by anti-factor Xa clotting assay and none by an anti-Xa amidolytic assay (S-2222). However, pentosan polysulphate is at least as potent as heparin on a weight basis in producing activation of lipoprotein lipase, shortening of the euglobulin clot lysis time and impairing the generation of factor Xa. Our data indicate that pentosan polysulphate has more marked effects in vivo than in vitro, that the action of the drug on clotting is mediated mainly via an At III-independent pathway, and that its effects are not confined to the coagulation system.
Chromatography of Antihemophilic Factor on Diaminoalkane- and Aminoalkane-Derivatized Sepharose
Authors: Morgenthaler J-J
Published: July 2018

Antihemophilic factor was chromatographed on a homologous series of diaminoalkane- and aminoalkane-modified Sepharose beads. Both factor VIII procoagulant activity (VIII:C) and protein are retarded on these columns when compared to their elution on a column made of unmodified Sepharose. Longer chains bind VIII:C and protein more tightly than shorter chains. No bound activity could be eluted with ethylene glycol. Increasing ionic strength eluted VIII:C and protein from aminoalkane- as well as from alkane-Sepharose. It seems likely that hydrophobic, rather than ionic forces, are responsible for the binding of VIII:C to the latter carriers.
Partial Characterization of a Fibrinolytic Inhibitor Produced by Cultured Endothelial Cells Derived from Human Umbilical Vein
Authors: Esnard F , Dupuy E , Dosne A M , Bodevin E
Published: July 2018

A preliminary characterization of a fibrinolytic inhibitor released by human umbilical vein endothelial cells in primary culture is reported. This molecule of Mr comprised between 2 × 105 and 106 and of μ2 mobility precipitates at 43% ammonium sulphate saturation and is totally adsorbed on Concanavalin A Sepharose 4 B. A possible relationship with a macroglobulins is discussed.
Factor IX Deventer-Evidence for the Heterogeneity of Hemophilia BM
Authors: Bertina R M , Linden I K van der
Published: July 2018

Factor IX Deventer was isolated from the plasma of a patient with severe hemophilia B. The patient was classified as BM because of an abnormal prolongation (2.1 times) of the ox-brain prothrombin time, that could be corrected by addition of antifactor IX serum. Experiments with the isolated factor IX Deventer showed that one of the two peptide bonds involved in the proteolytic activation of factor IX cannot be cleaved by physiological or non-physiological activators (XIa and RVV-X, respectively). Such a defect can explain why the molecule has no procoagulant activity. At present it is not clear why this defect makes factor IX Deventer such an effective inhibitor of the ox-brain prothrombin time. It is proposed that hemophilia BM is a heterogeneous disorder.
Diagnosis of Deep Vein Thrombosis by Combination of Doppler Ultrasound Flow Examination and Strain Gauge Plethysmography
Authors: Bounameaux H , Krähenbühl B , Vukanovic S
Published: July 2018

Doppler ultrasound flow examination, strain gauge plethysmography and contrast venography were performed in 160 lower limbs of 80 in-patients. Deep vein thrombosis (DVT) was suspected in 87 limbs. Using measurement of venous stop-flow pressure, the Doppler method had an overall sensitivity of 83%. By combined use of Doppler and Plethysmography, sensitivity was increased to 96%. Specificity was 62% and 51%, respectively. With a positive and a negative predictive value of 80% and 73%, respectively, the combination of both non-invasive methods cannot reliably replace venography in the diagnosis of DTV, although all (40/40) thromboses proximal to or involving the popliteal segment were detected by either Doppler and Plethysmography or both.

After exclusion of 14 patients (18%) suffering from conditions known to alter the results of these non-invasive methods, the positive predictive value of abnormal findings in both Doppler and Plethysmography was increased to 94% for suspected limbs, whilst negative predictive value of both negative Doppler and Plethysmography was 90%, allowing the avoidance of venography in these patients.
A Thiazole Compound with Potential Antithrombotic Activity
Authors: Nishizawa E E , Mendoza A R , Honohan T , Annis K A
Published: July 2018

A thiazole derivative, 4,5-bis(p-methoxyphenyl)-2-(trifluoromethyl)-thiazole was found to be a potent inhibitor of collagen-induced platelet aggregation, in vitro, using platelets from at least six species, including man. It was active in human platelet-rich plasma at a concentration of 1 ng/ml. While its antiplatelet activity was greater than that of flurbiprofen, its cyclooxygenase activity was equivalent to that of flurbiprofen. Also, compared to flurbiprofen, the thiazole had less anti-inflammatory activity in the hind-paw edema test. The thiazole derivative inhibited platelet aggregation following oral administration in five laboratory species. In the guinea pig it was active at 0.5 mg/kg. The LD50 in mice was greater than 1000 mg/kg (i.p.). This compound, which was designed through a systematic drug development program, may have high potential as an antithrombotic agent.
Secretion Defect in Platelets Stored at 4°C
Authors: Rao A Koneti , Murphy Scott
Published: July 2018

To understand the functional changes induced by storage, we have examined the adenine nucleotides of platelets stored for 72 hr at 22°C and 4°C. Ten platelet concentrates (PC) were stored at each temperature with five in each group having a final volume of 50 ml and 30 ml. The total ATP and ADP content of platelets decreased following storage in all 4 groups of PC, with the decrease being greater in the PC stored at 22°C than those at 4°C. The mean thrombin secretable ATP+ADP content of platelets from PC stored at 22°C and 4°C were 29.7% and 19.7% of the total content, respectively (p <0.001). Thus, cold stored platelets have a higher total content of ATP+ADP but secrete distinctly lesser amounts than 22°C stored platelets. Labeling of the metabolic pool adenylates with 14C-adenine revealed a greater decrease in the adenylate energy charge of the platelets stored at 4°C. The secretion defect demonstrated in cold stored platelets may be related to the inability of these platelets to maintain ATP homeostasis.
The Inhibition of Tissue Activator and Urokinase by Human Plasma
Authors: Walker J E , Ogston D
Published: July 2018

Plasma reduced the activity of urokinase and, to a lesser extent, tissue activator on unheated fibrin plates. After depletion of plasminogen by lysine-Sepharose the inhibitory effect of plasma was increased.

Normal plasma separated on DEAE-Sepharose or, after passage through lysine-Sepharose, on Sephadex G-100 provided fractions in three regions capable of inhibiting tissue activator. The high molecular weight fractions inhibited both activators, but after plasma fractionation on Sephadex 4B the inhibitory activities against tissue activator and urokinase eluted separately. Urokinase inhibition eluted with a2-macroglobulin: the inhibition of tissue activator was of higher molecular weight and of greater lability. Inhibition of tissue activator was found in two lower molecular weight regions: the fractions of one region inhibited tissue activator and coincided with the elution of fast-acting antiplasmin activity. The other region inhibited both tissue activator and urokinase. Alpha1 antitrypsin and antithrombin III eluted after both inhibitory regions.
Protein C Deficiency in a Dutch Family with Thrombotic Disease
Authors: Bertina R M , Broekmans A W , van der Linden I K , Mertens K
Published: July 2018

A rabbit antibody against human protein C was used for the quantitative estimation of protein C in plasma. In healthy individuals protein C antigen ranged from 0.65-1.45 U/ml. Plasma protein C antigen was found to be independent of either age or sex. Under influence of oral anticoagulant treatment the protein C antigen concentration decreased to 0.47 U/ml (at low intensity treatment) or 0.33 U/ml (at high intensity treatment). Using normal ranges of protein C and protein C/factor II and protein C/factor X ratios criteria were developed for the assessment of protein C deficiency. In a Dutch family with a history of thrombotic disease two members were found to have an isolated protein C deficiency, while a third one is suspected of protein C deficiency. In one case it was possible to confirm the diagnosis of suspected protein C deficiency during temporary withdrawal of the anticoagulant therapy.
Platelet Sensitivity to Prostacyclin and Thromboxane Production in Hyperlipidemic Patients
Authors: Strano A , Davì G , Averna M , Rini G B , Novo S , Di Fede G , Mattina A , Notarbartolo A
Published: July 2018

In 13 type II hyperlipidemics (10 males and 3 females; mean age 50.2 ± 10.6 years), in 10 type IV hyperlipidemics (7 males and 3 females; mean age 51 ± 13.3 years) and in 23 healthy age-and sex-matched controls, the following parameters were measured: plasma cholesterol; plasma TG; plasma C-HDL; VLDL, separated in a preparative ultracentrifuge; C-LDL; Apo B, with immunoelectrophoretic method; platelet sensitivity to prostacyclin; TXB2 formation in PRP; TXB2 in serum.

This study provides evidence for: 1. Reduced platelet sensitivity to prostacyclin, more evident in type II hyperlipidemia that provides an additional mechanism involved in increased platelet aggregation found in type II hyperlipidemia.

2. Enhanced TXB2 formation in PRP after thrombin stimulation (664.65 ± 142.18 pmol/108 platelets) only in type II hyperlipidemics and such enhanced formation was positively correlated to C-LDL (r = 0.53; p <0.05) and to Apo B (r = 0.62; p <0.05); serum TXB2 formation rate was also increased in type II hyperlipidemia.
Factor VIII Fractionation on Aminohexyl Sepharose with Possible Reduction in Hepatitis B Antigen
Authors: Austen D E G , Smith J K
Published: July 2018

The method of factor VIII purification by chromatography on aminohexyl Sepharose has been extended so that up to 100 ml of intermediate purity concentrate can be processed on an 8.6 ml column. The product has a specific activity of 1.8 International Units of factor VIII per mg of protein. Most of the fibrinogen is removed and antibodies to blood group substances A and B are not detectable by haemagglutination techniques. Hepatitis B antigen has been reduced to one sixteenth of that in the starting material, in preliminary experiments. The process has the added advantage that it concentrates the factor VIII relative to the starting material.
Inhibition of Platelet Aggregation by Ethanol in Vitro Shows Specificity for Aggregating Agent Used and Is Influenced by Platelet Lipid Composition
Authors: Fenn C G , Littleton J M
Published: July 2018

Ethanol at physiologically tolerable concentrations inhibited platelet aggregation in vitro in a relatively specific way, which may be influenced by platelet membrane lipid composition. Aggregation to collagen, calcium ionophore A23187 and thrombin (low doses) were often markedly inhibited by ethanol, adrenaline and ADP responses were little affected, and aggregation to exogenous arachidonic acid was actually potentiated by ethanol. Aggregation to collagen, thrombin and A23187 was inhibited more by ethanol in platelets enriched with saturated fatty acids than in those enriched with unsaturated fats. Platelets enriched with cholesterol showed increased sensitivity to ADP, arachidonate and adrenaline but this increase in cholesterol content did not appear to influence the inhibition by ethanol of platelet responses. The results suggest that ethanol may inhibit aggregation by an effect on membrane fluidity and/or calcium mobilization resulting in decreased activity of a membrane-bound phospholipase.
Reversible Inhibition of the In Vitro Coagulation of Human Plasma by Lectins
Authors: Freyssinet J-M , Thevenon D , Souque A , Suscillon M
Published: July 2018

Wheat germ agglutinin (WGA) and concanavalin A (Con-A) (also red kidney bean agglutinin, PHA) have been found to be inhibitors of plasma clotting in vitro. At 40 µg/ml and 250 µg/ml (4.4 µM and 10 µM in carbohydrate binding sites, final concentrations) respectively, WGA and Con-A are able to double the activated partial thromboplastin time of normal human control plasma. Their inhibitory effect is due to their capacity to interact with the carbohydrate portion of blood clotting factors. It is totally abolished in the presence of specific saccharides for WGA or Con-A and is attenuated in the presence of 4% (v/v, final concentration) of human erythrocytes. The action of WGA is mediated by its ability to interact with N-acetylneuraminic acid. When purified phospholipid vesicles plus kaolin are used as an activator instead of cephalidin, this effect persists to the same extent. These two lectins also prolong the plasma clotting time using Russell's viper venom plus purified phospholipid vesicles as an activator. Quick's time was also prolonged by WGA and Con-A but to a lesser extent in this case. WGA can interact directly with some purified blood clotting factors (IX, X and II) in a classical lectin-glycoprotein precipitin reaction. When assessed at individual factors level in whole plasma using clotting assays, direct inhibitions by WGA are only apparent.
In Vivo Interactions of Autoantibodies to Factor VIII with the Factor VIII Complex
Authors: Allain J P , Croissant M P , Lerolle D , Houbouyan L , Zuzel M , Frommel D
Published: July 2018

Two non-haemophilic elderly patients who had developed autoantibodies to factor VIII were studied over a period of 9 months to 5 years. Sequential measurements of antibody to factor VIII (anti-VIII: C), factor VIII coagulant activity (VIII: C), factor VIII coagulant antigen (VIII: CAg), factor VIII-related antigen (VIIIR: Ag), and factor VIII ristocetin cofactor (VIII: WF) were performed. Before treatment, low VIII: C, norlnal or increased VIII: CAg and high VIIIR: Ag levels were found and were indicative of the presence of circulating immune complexes. Immunosuppressive therapy induced progressive correction of VIII: C and VIIIR: Ag values. High levels of VIII: CAg subsided in the patient who relapsed. It is suggested that antibodies to factor VIII bind and remove VIII: C from the circulation thereby inducing an increased synthesis of VIII: CAg which may be associated with an augmented release or production of VIIIR: Ag.
The State of Actin Polymerization in Tetracaine-Treated Platelets
Authors: Davies Gregg E , Palek Jiri
Published: July 2018

Although there is considerable evidence that platelet activation is associated with polymerization of actin, it is not known whether there is some pre-existing F-actin even before activation. We have examined the state of actin polymerization in nonactivated platelets by deoxyribonuclease assay of G-actin and total actin. To fully suppress activation, platelets were prepared in the presence of tetracaine. The G-actin/total actin ratio in tetracaine-treated platelets prepared by three different methods is significantly less than one (average of all results = 0.61). We conclude that about 39% of total actin in nonactivated tetracaine-treated platelets may be present as F-actin.
The Use of Desmopressin Acetate (DDAVP) as a Test of the Fibrinolytic Capacity of Patients – Analysis of Responders and Non-Responders
Authors: Brommer E J P , Barrett-Bergshoeff M M , Allen R A , Schicht I , Bertina R M , Schalekamp M A D H
Published: July 2018

Intravenous infusion of desmopressin (DDAVP, 0.4 μg/kg b.w. in 12’) causes an increase in the level of extrinsic plasminogen activator, measured in plasma euglobulin fractions with added C1-inactivator on fibrin plates. A poor response or no response at all was elicited in two out of 21 patients with spontaneous thrombosis, 18/38 with hyperlipoproteinaemia and 10/14 with terminal renal insufficiency requiring haemodialysis.

Haemodilution during the first 30’ after starting the DDAVP-infusion occurred both in responders and in non-responders; so did haemodynamic reactions: increase in heart rate, drop in diastolic blood pressure, facial flushing. The rise of fibrinolytic activity was shown not to be associated with decreased hepatic blood flow. Normal factor VIII-rises in “non-responders” indicate the responsiveness of the receptive organs, including the hypothalamus, to DDAVP.

Despite a normal baseline level of fibrinolytic activity in the blood, as occurs for instance in terminal renal insufficiency, the vascular endothelium may be refractory to stimulation. In some patients, especially in type IV hyperlipoproteinaemia, a selective defect of the release of plasminogen activator is postulated. In subjects with low fibrinolytic activity at rest, as observed in spontaneous thromboembolism and in hypertriglyceridaemia, the failure to release plasminogen activator upon stimulation with DDAVP might be a consequence of an impairment of synthesis as well.
Inhibition of Human and Rat Platelet Aggregation by Extracts of Mo-er (Auricularia auricula)
Authors: Agarwal K C , Russo F X , Parks R E
Published: July 2018

Hot water extracts of Mo-er (1 gm by 15 ml of water), an oriental food (Auricularia auricula), inhibit strongly both human and rat platelet ADP-induced aggregation. HPLC analysis of two varieties of Mo-er, A.auricula and A.polytricha (a black tree fungus), shows that they contain adenosine (Ado), 133 and 154 micrograms per gram of dry fungus, respectively. The inhibition of ADP-induced platelet aggregation by Mo-er extracts and by Ado was compared. Mo-er extracts caused a more rapid onset and a longer duration of inhibition than produced by equivalent amounts of Ado. Furthermore, Mo-er extract treated with adenosine deaminase to degrade the Ado retained the capacity to inhibit platelet aggregation. The inhibitory effects of Mo-er extracts on ADP-induced human platelet aggregation are greatly potentiated by the inhibitors of cyclic AMP phosphodiesterase such as oxagrelate (phthalazinol) and papaverine. The inhibition of platelet aggregation is only partially blocked by 2’,5’-dideoxy-adenosine (DDA), an inhibitor of platelet adenylate cyclase and 5’-deoxy, 5’-methylthioadenosine (MTA), an antagonist of Ado receptors. ADP-induced rat platelet aggregation is strongly inhibited by Mo-er extracts, but not by Ado. This inhibition is not reversed by either DDA or MTA. These findings indicate that Mo-er extracts contain an agent (or agents) in addition to Ado, that blocks platelet aggregation by a mechanism that does not involve the platelet cyclic AMP system.
Effects of Ethanol Intoxication and Hangover on Plasma Levels of Thromboxane B2 and 6-Keto-Prostaglandin F1α and on Thromboxane B2 Formation by Platelets in Man
Authors: Kangasaho M , Hillbom M , Kaste M , Vapaatalo H
Published: July 2018

We detected a significant decrease in plasma thromboxane B2 (TXB2) and 6-keto-prostaglandin F1α (6-keto-PGF1α) levels together with a significant increase in plasma 6-keto-PGF1α/TXB2 ratio in young healthy non-alcoholic male volunteers after acute ingestion of ethanol (1.5 g/kg). Paradoxically, during ethanol intoxication and the following hangover a significant increase in ADP-induced formation of TXB2 by platelet rich plasma could be observed, which suggests that ethanol intoxication via some unknown mechanism sensitizes platelets to produce TXB2. Whether these observations contribute to the increased risks of subarachnoid haemorrhage or ischaemic brain infarction among occasional heavy drinkers recently described by us remains to be proved.
Repeated Occurrence of Skin Necrosis Twice Following Coumarin Intake and Subsequently During Decrease of Vitamin K Dependent Coagulation Factors Associated with Cholestasis
Authors: Hofmann V , Frick P G
Published: July 2018

A female patient is described who developed skin and subcutaneous fat necrosis on two occasions after intake of acenocoumarol.

Several months later identical skin changes occurred during an episode of cholestasis associated with a prolongation of the prothrombin time to an extent comparable with therapeutic anticoagulation; intake of oral anticoagulants could be excluded.

This association gives new insights in the pathogenetic mechanisms responsible for the so-called coumarin necrosis and indicates that it may be not due to drug toxicity or allergy.
Inhibition of Activated Coagulation Factor VII by Normal Human Plasma
Authors: Dahl P E , Abildgaard U , Larsen M L , Tjensvoll L
Published: July 2018

An amidolytic assay system with tissue thromboplastin (Tpl), purified coagulation factors VII and X, and the chromogenic substrate S-2222 was developed. Antithrombin III (AT) accounts for about one third of the total inhibition exerted by normal plasma in this test system. This effect of AT was prevented by adding purified AT blocking antibodies. Normal plasma and serum showed approximately similar inhibitory effects. The inhibition was probably directed against activated factor VII (F VIIa). Gel filtration of adsorbed normal plasma on Ultrogel AcA 34 showed three inhibitory peaks which were different from AT.
Home-Diagnosis of Deep Venous Thrombosis with Impedance Plethysmography
Authors: Peters S H A , Jonker J J C , de Boer A C , den Ottolander G J H
Published: July 2018

In order to assess the value of I.P.G. for the diagnosis of D.V.T. in general practice, an I.P.G. was carried out by a skilled technician in 255 consecutive patients with suspected D.V.T. at home. Ascending venography was carried out in 185 of these patients. In addition, blood for assay of AT III, platelet count, fibrinogen, a2-antiplasmin, ethanol gelation test and spontaneous platelet aggregation was collected at the time the I.P.G. was performed. In 61 patients (33%) venography showed the presence of D. V.T., and was negative in the remaining 124 patients. I.P.G. was positive in 51 of the 61 patients with D.V.T., a sensitivity of 84%. I.P.G. was normal in 115 of the 124 patients with a negative venogram, a specificity of 93%. The sensitivity of the I.P.G. for proximal vein thrombosis was 92% and for calf vein thrombosis 68%. Mean a2-antiplasmin concentration was significant (p Ã0.05) lower (101 ± 15%, mean ± SD) inpatients with D.V.T. compared with patients with a normal venogram (107 ± 11%, mean ± SD). No differences between the two groups were observed in the other coagulation parameters assayed, and none was of diagnostic value, either alone or in combination with I.P.G. This study shows that I.P.G. is of potential value for the home diagnosis of D.V.T., in particular proximal vein thrombosis. This is potentially clinically useful, because these thrombi are thought to carry a high risk for pulmonary embolism.
Effects of Etamsylate on Platelet Functions and Arachidonic Acid Metabolism
Authors: Okuma M , Takayama H , Sugiyama T , Sensaki S , Uchino H
Published: July 2018

The effects of etamsylate on human platelet aggregation and ATP release as well as on the arachidonate metabolism by the platelet have been studied. Etamsylate enhanced these platelet functions induced by arachidonic add (AA), thromboxane A2, collagen and caldum ionophore A23187 but not those induced by ADP and epinephrine. In experiments with cyclooxygenase-inhibited platelets, AA-induced platelet aggregation was completely inhibited and it was not enhanced by etamsylate, while A23187-induced aggregation was partially inhibited and this aggregation was enhanced by etamsylate. Platelet AA metabolism including thrombin-induced AA liberation from phospholipids as well as the lipoxygenase and cyclo-oxygenase pathways was not significantly affected by etamsylate. These results suggested that etamsylate enhanced platelet response to thromboxane A2 and calcium ionophore and that this could be included as a mechanism for its potentiating effect on platelet functions.