bluuebunny/crossref_metadata_2025 huggingface dataset:
In vitro Effects of Aspirin in Fibrinolysis
Authors: Iatridis Panayotis G. , Iatridis Sotirios G. , Markidou Sophia G. , Ragatz Barth H.
Published: April 2009

In in vitro studies, aspirin inhibited the lytic activity of streptokinase (SK), urokinase (UK), plasmin, and of euglobulins prepared from normal and Hageman deficient human plasmas. Aspirin also inhibited the generation of activator activity in the plasminoplastin generation test assay. This anti-fibrinolytic effect of aspirin was not due to its acid pH. Chicken plasma being deficient in Hageman factor and in proactivator exerted also a very potent anti-SK and anti-UK effect.
Dilution of Haemophilic Plasma Used as a Reagent in the Determination of Anti-Haemophilic Factor A (Factor VIII)
Authors: Bouma B.N. , Starkenburg Anneke E.
Published: April 2009

Haemophilic plasma used as a reagent in the determination of factor VIII can be used more economically by dilution (1:1, v/v) with citrated Michaelis buffer. Moreover, dilution results in an increased sensitivity and in a slight increase in the accuracy of the method in comparison to the use of undiluted haemophilic plasma.
Platelet Membrane Function Studies on Platelets from Patients with Hereditary Thrombopathic Thrombocytopenia
Authors: Baadenhuijsen H. , Haanen C.
Published: April 2009

Routine clotting tests, general platelet function tests, platelet Na+ and K+ concentrations, the influx and efflux kinetics of 86Rb+ (as K+ analogue) and the osmotic resistance have been studied in platelets from patients with a dominant hereditary macrocytic thrombopathic thrombocytopenia. Calculated on a cell-volume basis the pathological platelets showed no abnormalities in the concentration gradients for Na+ and K+. In all patients a normal active uptake and a strikingly decreased passive efflux rate of 86Rb+ from the platelets was observed. Ouabain increased the efflux rate of 86Rb+ from control platelets, whereas no or weak efflux-increasing effect was observed in the pathological platelets. The platelets of all patients studied showed a shift towards a more resistant osmotic fragility curve, possibly caused by an increased surface to volume ratio of the cells. The findings are explained in terms of a pathological platelet membrane which is more rigid in structure and which requires more drastic stimuli in order to function properly.
Increase of a Plasma Factor Involved in Ristocetin-Induced Platelet Aggregation after Exercise
Authors: Stibbe J. , van der Plas P.M.
Published: April 2009

Ristocetin-induced platelet aggregation was increased after exercise in 5 healthy volunteers. It was shown that this was the result of the increase of a plasmatic factor.
Correction of the Haemostatic Defect in Haemophiliacs without Apparent Correction of the Coagulation Defect
Authors: Serneri Neri , Gensini G.F. , Gensini Abbate
Published: April 2009

The evaluation of microhaematuria may be considered as a measure of the haemostatic defect of haemophiliacs in nonhaemorrhagic periods. In order to study the relationship between coagulation disorder and haemostatic defect we have administered small amounts (1 U and 3 U/kg) of AHG and of factor IX (1 U/kg) to 12 haemophiliacs (10 A and 2 B) and we have examined the effects on coagulation and microhaematuria. Microhaematuria was determined by the measurement of urinary radioactivity/24 h, after infusion of autologous RBC labelled with 51Cr, for 11 consecutive days (4 days before and 7 after the administration). Coagulation was investigated by thromboelastography, PTT, Quick’s time, PCI, factor VIII and IX activity assays, fibrinogen assay, and euglobulin lysis time. During the period of investigation, the patients remained in bed. In controls, factor VIII administration did not affect microhaematuria. On the other hand, in all haemophiliacs, factor VIII and IX administration significantly reduced microhaematuria, although the administered dose was not able to modify the coagulation defect. In all subjects the reduction of microhaematuria lasted at least 5 days. The correction of the haemostatic defect, without improvement of the clotting disorder, and its persistence for several days suggest that factor VIII is involved in the composition of the vascular wall and in its functional integrity. Moreover, on the basis of these results it is possible to carry out a rational prophylaxis of the haemorrhagic episodes using small doses of factor VIII, by determining the duration of the correction of the haemostatic defect for each subject.
Synthetic, Low Molecular Thrombin Inhibitors. A New Concept of Anticoagulants?
Authors: Markwardt F.
Published: April 2009

Biochemical, pharmacological and first clinical findings on synthetic, low molecular weight inhibitors of serine proteinases of the blood considered to be therapeutically relevant thrombin inhibitors are reviewed. Their effect is due to an inhibition of the thrombin-fibrinogen reaction as well as of other effects of thrombin in the coagulation system. Synthetic thrombin inhibitors represent approaches to the development of new types of anticoagulants.
Platelet Shape Change: Induction by Trypsin and Release of an Acidic Macroglycopeptide from Washed Human Platelets and from those of Three Cases of Glanzmann’s Thrombasthenia
Authors: Nurden A.T. , Butcher P.D. , Bredoux R. , Caen J.P.
Published: April 2009

Trypsin, which induced a rapid shape change followed by a large irreversible aggregation in gel-filtered control human platelets, induced an apparently normal shape change but no aggregation in gel-filtered thrombasthenic platelets. Addition of soybean trypsin inhibitor after the induction of the shape change in gel-filtered control platelets inhibited both further shape change and subsequent aggregation. Rapid release of an acidic macroglycopeptide was induced by trypsin from both control and thrombasthenic washed platelet suspensions with a significant part of the release occurring in a time scale parallel with the trypsin-induced shape change. The macroglycopeptide, which contained most of the released sialic acid, was derived from the largest of the native platelet membrane glycoproteins which is probably the major sialylglycoprotein of the platelet membrane.
Effect of Temperature on Platelet Interaction with Subendothelium Exposed to Flowing Blood
Authors: Turitto V.T. , Baumgartner H.R.
Published: April 2009

Platelet interaction with subendothelium exposed to whole blood in an annular perfusion chamber was investigated at 37, 20 and 4 °C. Decrease in temperature caused a significant decrease in the coverage of the subendothelial surface by platelets as well as in the formation of platelet microthrombi. In contrast, the total percentage of platelets in their initial state of attachment (contact) was increased. The corresponding decrease in platelets spread onto the surface (adhesion) suggested that the transition reaction from platelet contact to adhesion was significantly diminished by the reduction in temperature. Results of aggregation experiments in platelet-rich plasma with adenosine diphosphate and collagen suspensions were consistent with a decreased adhesion reaction to collagen.Mass transfer theory was used to compare platelet deposition results at 37 and 20 °C and suggested on of the following: (1) a platelet diffusivity in whole blood which was significantly more sensitive to temperature than the diffusibility of molecular solutes or (2) a significant decrease in the rate of the platelet attachment reaction at 20 °C.
Von Willebrand’s Disease with Normal Factor VIII Activity in a Homozygote
Authors: Holmberg Lars , Rašović Nada , Nilsson Inga Marie
Published: April 2009

An atypical form of von Willebrand’s disease is described in a patient apparently homozygous for an abnormal autosomal gene. The characteristics of the disease were a low factor VIII antigen level, reduced platelet adhesiveness and prolonged bleeding time, but factor VIII activity was normal and platelet aggregation by ristocetin was nearly normal. Further studies showed that the patient had a high-molecular-weight factor VIII compound, most of which, however, seemed to be somewhat smaller (less aggregated) than that in normal plasma.
Effects of Sodium Nitroprusside and Other Pentacyanonitrosyl Complexes on Platelet Aggregation
Authors: Glusa Erika , Markwardt F. , Stürzebecher J.
Published: April 2009

The influence of sodium nitroprusside (SNP) and other nitric oxide complexes on platelet function is studied. SNP inhibits platelet aggregation and the release reaction, while pentacyanonitrosyl complexes of manganese, tungsten, and molybdenum are ineffective. Since nitrosylperchlorate exerts the same inhibitory effect on platelet aggregation the nitrosyl cation is supposed to be the constituent of SNP responsible for inhibition.
Adhesion of Human Blood Platelets to Glass and Polymer Surfaces
Authors: Mohammad Fazal , Hardison M.D. , Glenn C.H. , Morton B.D. , Bolan J.C. , Mason R.G.
Published: April 2009

Platelet adhesion to glass, polyethylene, polyvinyl chloride, and Cuprophane has been studied by means of a method specific for quantitation of adhesion. Platelets adhered in larger numbers to polyethylene and polyvinyl chloride than to Cuprophane or glass regardless of the anticoagulant used. In citrated plasma, fewer platelets adhered to glass than to Cuprophane, although adhesion to glass and Cuprophane was nearly the same when EDTA or heparin was used as anticoagulant. The number of adherent platelets decreased appreciably from values obtained with citrated platelet-rich plasma, when EDTA or heparin was used as anticoagulant. Adhesiveness of normal platelets increased with age. A number of different pharmacologic and other agents were found to inhibit platelet adhesion to artificial surfaces. Acetylsalicylic acid and glucosamine were less effective inhibitors than sulfinpyrazone, imipramine, desipramine, amitriptyline, chlorpromazine, or PCMB. Penicillin did not inhibit adhesion. Donors deficient in factors VIII, XI, or XII or donors with von Willebrand’s disease showed normal platelet adhesiveness. Adhesiveness was markedly low in tests with blood from afibrinogenemic or thrombasthenic patients. Decreased adhesiveness of afibrinogenemic platelets could be corrected by addition of fibrinogen.
Investigation of the Binding Component of the Ethanol-Insoluble Metabolic ADP of Human Platelets and its Relation to the Release Reaction
Authors: French P.C. , Wachowicz B.
Published: April 2009

The metabolic nucleotides of washed human platelets can be subdivided into ethanol-insoluble (almost all as ADP) and ethanol-soluble pools. About 5 % of the total radioactively labelled metabolic nucleotides are found in the ethanol-insoluble pool. At least part, if not all, of the ethanol-insoluble ADP is bound to platelet actomyosin (thrombosthenin). The specific activity of the ADP in this pool is the same as that of the rest of the metabolic ADP and is not ‘superactive’. Addition of thrombin to washed human platelets previously incubated with [3H]-adenine did not alter the level of ethanol-insoluble ADP, as compared to similarly treated control platelets. Similarly, there were no changes in the radioactive ADP content of actomyosin extracted directly from washed human platelets after exposure to thrombin, as compared to controls. The metabolic ADP content of control platelet actomyosin might reflect the in vivo situation, but the possibility exists that mechanical damage during platelet isolation from plasma and subsequent handling could have caused the exchange. No evidence presented here indicates the involvement of platelet actomyosin in the platelet release reaction mechanism.
In vitro Granulocyte-Platelet Rosette Formation Mediated by an IgG Immunoglobulin
Authors: Zeigler Zella
Published: April 2009

In vitro granulocyte-platelet rosette formation (adherence of platelets to granulocytes) was noted as a cause of falsely low electronic platelet counts in two patients. Investigations showed that this phenomenon was caused by a plasma factor, contained in the IgG fraction; further, activity was completely inhibited with anti-IgG antiserum. Rosette formation could be detected with either autologous or isologous platelets and granulocytes. Moreover, repeated adsorptions of patients’ plasma with isologous platelets removed the rosetting factor.
Decreased Susceptibility to Thrombin and Collagen Platelet Aggregation in Man Fed a Low Fat Diet
Authors: Iacono J.M. , Binder R.A. , Marshall M.W. , Schoene N.W. , Jencks J.A. , Mackin J.F.
Published: April 2009

A study was conducted in seven males and eight females to determine the effect of feeding 25 and 35% fat calories on plasma lipids, blood clotting parameters and platelet aggregation. A statistically significant reduction in thrombin- and collagen-induced aggregation was observed at the end of the 25 %-fat-calorie period. At the end of the 35 %-fat-calorie period the thrombin- and collagen-induced aggregation tests rebounded to the predietary level. Platelet counts rose significantly and white blood cell counts decreased by the end of the 25 %-fat-calorie period. Both platelet counts and white blood cell counts returned to predietary levels at the end of the 35 %-fat-calorie period. Plasma cholesterol decreased an average 15% at the end of the 25 %-fat-calorie period and remained at the lowered level throughout the 35 %-fat-calorie period. It is suggested that levels of total and saturated fat in the diet are significant factors affecting the aggregation tendency of blood platelets.
Exchange Transfusions with Frozen Blood
Authors: Kreuger Anders , Blombäck Margareta
Published: April 2009

In three newborn infants exchange transfusions were performed with previously frozen red blood cells resuspended in a balanced albumin-saline solution or in fresh-frozen plasma. After the exchange a considerable decrease of platelets, fibrinogen, coagulation factors II, V, VIII and X and antithrombin III was noticed but no signs of increased bleeding tendencies. The restoration of the coagulation factors was more rapid when fresh-frozen plasma was used. For newborn infants with suspected or manifest coagulation disorders and for newborn infants needing more than one exchange transfusion, frozen, thawed and washed red blood cells should be resuspended in fresh or fresh-frozen plasma when used as transfusion blood.
Platelet Aggregometry and Anti-Platelet Isoantibodies
Authors: Pogliani E. , Deliliers Lambertenghi , Ferrari R. , Pozzoli E. , Cofrancesco E. , Praga C.
Published: April 2009

102 sera from polytransfused patients have been screened in platelet aggregometry. Anti-human platelet isoantibodies, tested against ‘responsive’ human platelets in PRP, give in the aggregometer a decrease in optical density recorded as a sigmoidal curve. In the first step of reaction PF3 availability suggests that the primary action of antibody is to damage the platelet membrane. The second step might be a true aggregation (an ADP-mediated platelet clumping) or a platelet lysis, depending on the type and the potency of antibody, on the type of platelets (normal or thrombasthenic) and on some experimental conditions. These conclusions, confirmed by electron microscopy findings, suggest that aggregometry is a very rapid and simple method of detecting platelet antibodies.
Studies on Catabolism of 125I-Labelled Fibrinogen in Normal Rabbits and in Rabbits with Indwelling Intravenous Catheters: Methodologic Aspects
Authors: Mahn Ingo , Müller-Berghaus Gert
Published: April 2009

The catabolism of rabbit fibrinogen labelled with radioactive iodine was studied over a period of 7–9 days in normal rabbits and in rabbits with indwelling intravenous catheters. The labelled fibrinogen was highly clottable and homogeneous on immunoelectrophoresis and disc electrophoresis. The protein-bound 125I-activity amounted to at least 99%. Normal rabbits with a weight between 1.6 and 2.2 kg exhibited a mean plasma volume of 41.65 ml/kg. A mean half-life time of 1.69 days and a mean fractional catabolic rate of 59.8% of the plasma fibrinogen pool per day was computed by tracing labelled fibrinogen. The absolute catabolic rate revealed a mean value of 58.7 mg/kg body weight/day. Comparable results were obtained for all three labelled fibrinogen batches. A siliconized polyvinyl tubing with an outer diameter of 2.0 mm inserted into a jugular vein up to a length of 10–12 cm and indwelling for more than 10 days did not significantly influence the parameters studied for controlling the fibrinogen catabolism except for the absolute catabolic rate of 112.8 mg/kg/day which differed significantly from that of the control group. Thus, the indwelling intravenous catheter had no or only a minor effect on the activation of intravascular coagulation.
Cyclical Changes in Coagulation Factors Associated with the Use of Progestational Agents
Authors: McGrath K.M. , Castaldi P.A.
Published: April 2009

The activity of factors II, VII, VIII, IX, X and fibrinogen and factor VIII antigen levels were followed during a single menstrual cycle in three females using oral contraceptive agents, and in two controls. Marked cyclical variation occurred in the activity of factor VII and VIII, but not in factor VIII antigen levels. Less marked changes occurred in factor II and fibrinogen.
Controlled Trial of Platelet Anti-Aggregating Agents and Subcutaneous Heparin in Prevention of Postoperative Deep Vein Thrombosis in High Risk Patients
Authors: Dechavanne M. , Ville D. , Viala J.J. , Kher A. , Faivre J. , Pousset M.B. , Dejour H.
Published: April 2009

In a prospective randomised trial, three groups of 20 patients each were compared. A first group served as a control, a second group received dipyridamole and acetylsalicylic acid and a third group received low doses of heparin. The incidence of deep vein thrombosis determined by the 125I-fibrinogen test was 40 % in the first group, 50 % in the second group, and 5 % in the third group. The differences between the heparin group and the two other groups are statistically significant. No wound complication and no haematoma at the injection site occurred.
Interference on the Haemostasis in Dogs with Induced Coagulopathies by Drugs Affecting the Platelet Function
Authors: Johnsson Hans , Olsson Per
Published: April 2009

Acetylsalicylic acid and phenylbutazone increased the bleeding significantly from standardized wounds in dogs defibrinogenated with Defibrase. Administration of dipyridamole and Xylocain® had no effect. The results were the same in dogs treated with warfarin sodium. The results demonstrate the value of using laboratory animals with an induced coagulopathy when establishing the effect on the haemostasis exerted by drugs known in vitro to interfere with platelet functions. Acetylsalicylic acid and dipyridamole did not alter the activity of the K-vitamin-dependent coagulation factors, factors V, VIII, platelet count or fibrinogen concentration.
Mechanism of Thrombocytopenia Induced in Mice by Anti-Platelet Serum
Authors: McDonald T.P. , Clift Rose
Published: April 2009

Although anti-platelet serum is frequently used to produce thrombocytopenia, the mechanism of how platelets are removed from the circulation is poorly understood. In vitro studies indicated that anti-platelet serum caused platelet aggregation, whereas normal rabbit serum did not. The aggregation was dose related; at the lower dose, aggregated platelets were shown to deaggregate and platelets released from the aggregates responded normally to ADP but not to collagen. In mice whose platelets were previously labeled with Na235SO4, anti-platelet serum caused an increase in the amount of 35S mucopolysaccharides (MPS) recovered from the kidneys. No increase in radioactivity was found in the lungs, livers, or spleens of similarly treated mice. The data suggest that platelet specific anti-serum causes platelets to aggregate leading to ADP (and consequently 35S-MPS) release; the accumulation of 35S in kidneys may be due to removal of MPS and/or platelets from the circulation.
The Appearance of Schistocytes in the Peripheral Blood in Correlation to the Degree of Disseminated Intravascular Coagulation
Authors: Heyes Heinrich , Köhle Walther , Slijepcevic Bozena
Published: April 2009

The infusion of thrombin in rats induced a disseminated intravascular coagulation (DIC) with haemolysis and schistocytosis. The number of schistocytes was found to be correlated to fibrinogen catabolism, plasma haemoglobin level and to the extent of fibrin deposition in the renal glomeruli in the early phase only. Later, no correlation could be observed, indicating a time-dependent behaviour of schistocytosis. The results suggest that a large number of schistocytes in blood smear is suspicious for DIC. These studies also support the concept that fibrin depositions in the blood vessels could play a role in the production of red cell fragmentation by mechanical destruction.
Inhibition of Platelet Aggregation by Acetylsalicylic Acid and other Inhibitors
Authors: Seuter Friedel
Published: April 2009

Effects on platelet aggregation were examined of acetylsalicylic acid (ASA), indomethacin and a number of other agents including dipyridamole, phenylbutazone and sulfinpyrazone under standardized conditions. The Born turbidometric method of measuring platelet aggregation was used with collagen as the stimulus for aggregation. ASA and indomethacin were shown to be among the most potent inhibitors of aggregation, being active at minimal effective concentrations of 1–3 μg/ml using a 10 min time of pre-incubation with the platelet-rich plasma (degree of aggregation inhibition was time dependent). Most of the other agents tested were also active in vitro and both prostaglandin El and adenosine were more potent than ASA or indomethacin. However, these agents were shown not to exert significant inhibitory effects when administered orally to rats (dose 10 and 30 mg/kg). ASA proved to be effective in doses as low as 3 mg/kg, and indomethacin in doses as low as 1 mg/kg orally. The inhibitory effects of ASA on aggregation remained for several days after a single oral dose, whereas the effects of indomethacin disappeared within 24 h.
Effect of Amadori-Type Sugar Derivatives of Poly-L-Lysine on Platelet Aggregation
Authors: Mester M. , Kraska B. , Crisba J. , Mester L.
Published: April 2009

Fully substituted Amadori-type sugar derivative of Sigma type V-A poly-L-lysine does not induce platelet aggregation, but inhibits 30 % of the platelet aggregation induced by collagen.
Induction of a Labile Chicken Plasma Coagulation Factor by Choline: Dose-Response Relations, Specificity, and Effects of Protein Synthesis Inhibitors
Authors: Sørbye Øyvind
Published: April 2009

Minimum oral doses of 21.5 mg/kg choline chloride were required for induction of maximum plasma level of the choline-dependent component (π-factor) of the labile factor activity complex in chickens on a choline-deficient diet. Several derivatives and potential precursors of choline were inactive as substitutes for the free base. After intravenous injections of optimal doses of choline, an initial lag of about 8 min was followed by a linear increase in π-factor level reaching the maximum level about 31 min after the injection. The response was blocked and arrested by simultaenous and delayed injections, respectively, of puromycin and cycloheximide. After intravenous injections of actinomycin D, the response to choline was unaffected by a delay of up to 40 min, but completely abolished by a further delay of 90 min or more. The data suggest that the plasma level of π-factor is governed by the supply of choline by regulation of a pre-translational step in the biosynthesis of π-factor.
Occurrence of Cl Inactivator and Other Proteinase Inhibitors in Euglobulin Fractions and Their Influence on Fibrinolytic Activity
Authors: Kluft C.
Published: April 2009

Considerable amounts of Cl inactivator and inter-α-trypsin inhibitor precipitate during euglobulin fractionation of human plasma. The amount precipitated depends on the ionic strength and the pH during the fractionation procedure. In contrast, α2-anti-trypsin, α2-macroglobulin and antithrombin III are present in euglobulin fractions in trace amounts only. The fibrinolytic activity of the euglobulin fractions is inhibited by the endogenous Cl inactivator, particularly as shown by comparison of normal and hereditary angioneurotic edema (HANE) plasma.
Pretreatment with Heparin in Thrombolytic Therapy with Urokinase
Authors: Bizzi Bruno , Leone Giuseppe , Accorrà Franca
Published: April 2009

Initially, we administered urokinase to five patients according to the following schedule: 500,000 CTA U during the first 10 min, then 250,000 CTA U/h for 12 h. Using this modality, we noted the appearance, during the first hours of treatment, of hypercoagulability. We then choose to modify the schedule by pretreatment with 7,500 U i.v. of heparin, followed promptly by 250,000 CTA U/h of urokinase (without a loading dose). This obviated the appearance of hypercoagulability without reducing the fibrinolytic effect of treatment and without producing hemorrhagic complications.
Platelet-Collagen Interaction
Authors: Balleisen L. , Marx R. , Kühn K.
Published: April 2009

Type I collagen from calf skin, collagen modified by pepsin treatment, methylation, succinylation or deamidation, as well as the α-chains and cyanogen bromide peptides of the α1-chain, were investigated with respect to their capacity to induce aggregation of human platelets. These preparations permitted an evaluation of the efficacy of the amino acid sequence, triple helical conformation, and various fibrillar structures in platelet aggregation. All collagens in dissolved form (collagen dissolved at acid pH, pep sin-treated, methylated, deamidated, and succinylated collagen) induced platelet aggregation only after fibril formation. The arrangement of molecules within fibrils is of secondary importance. Modification of the side chains of amino acid residues affects primarily the formation of fibrils. The effect of these side chains on platelet aggregation is masked by the overwhelming potency of the fibrillar forms.
Ionophore A 23187: Some Effects on Platelet Aggregation and Clot Retraction
Authors: Bottecchia Domenico , Fantin Glampaolo , Gruppo Paolo , Nassuato Gino
Published: April 2009

The ionophore for divalent cations, A 23187, induces platelet aggregation and clot retraction. Acetylsalicylic acid has a potentiating effect on the aggregation induced by A 23187 in platelet-rich plasma, while it inhibits the aggregation of washed platelets. Acetylation of plasma proteins could be the reason of the increased platelet aggregation induced by A 23187 in the presence of acetylsalicylic acid. Platelet aggregation by A 23187 is probably activated by the passage of Ca2+ through the platelet membrane(s); the aggregation does not depend on the release reaction. By contrast with aggregation, clot retraction by A 23187 requires increased availability in the intracellular space of both Ca2+ and Mg2+.
Correlations between Radioiodine Uptake and Blood Viscosity Factors in Hypothyroid and Hyperthyroid States
Authors: Dintenfass L.
Published: April 2009

A study of blood viscosity factors was undertaken in six hypothyroid and eleven thyrotoxic patients (females) whose thyroid function was defined by means of radioiodine uptake and protein bound (PB) 131I tests. Results indicate that: (i) significant differences exist between hypothyroid and hyperthyroid groups in correlations between radioiodine tests and blood viscosity factors (and fibrinogen levels); (ii) blood viscosity in thyrotoxic patients decreases as the degree of thyrotoxicity increases, while an opposite phenomenon is observed in hypothyroid patients, and (iii) degree of rigidity of the red cells is associated with the radioiodine uptake and PB 131I tests, the correlations being significant and negative.
Binding of 14C-ADP by Thrombasthenic Platelet Membranes
Authors: Legrand C. , Caen J.P.
Published: April 2009

We have measured the binding of 14C-ADP to isolated human platelet membranes by a technique using 0.8-μm Millipore filters to separate unbound tracer from membrane-bound nucleotide. The binding was dependent on the time of incubation and on the nucleotide concentration in the medium. The affinity constant was found to be comprised between 0.35 × 106 and 0.55 × 106 M-1. Platelet membranes prepared from different thrombasthenic patients bound 14C-ADP with the same kinetic parameters as those from normal subjects. The affinity constant as determined for two of these thrombasthenic platelet membrane preparations was in the normal range.
Dose-Dependent Influence of Acetylsalicylic Acid on Platelet Functions and Plasmatic Coagulation Factors
Authors: Loew D. , Vinazzer H.
Published: April 2009

Lysine salt of acetylsalicylic acid (ASA) was given to ten patients by intravenous infusion. Blood samples taken at intervals during the infusion permitted the examination of the influence of the dose of ASA on platelet functions. Aggregation was significantly reduced when 50 mg ASA had entered circulation, while a diminution of PF 3 and PF4 availability could only be demonstrated when the dose had reached 500 and 200 mg, respectively. In order to exclude a longer latency time for the diminution of PF 3 and PF 4 availability, a second series of ten patients received intravenous injections of 100 and 300 mg ASA, respectively. From these patients, blood was taken 1 h after the injection. The decrease of PF 3 and PF 4 availability in these cases was comparable to the results of the first group. In a third series of patients, a daily intravenous dose of 2,000 mg ASA was given. In these cases, a moderate decrease of factors II, VII, IX and X was observed. Since the appearance of a PIVKA effect could also be demonstrated, vitamin K antagonism was assumed when a high dose of ASA was given for an extended length of time.
Differences in the Reactivities of Human Urokinase and the Porcine Tissue Plasminogen Activator
Authors: Thorsen Sixtus , Astrup Tage
Published: April 2009

It has previously been shown, that large differences exist between the effects of 6-aminohexanoic acid or α1-antitrypsin on fibrinolysis caused by a porcine tissue plasminogen activator or by human urokinase, while insignificant differences exist between the effects of a number of natural protease inhibitors on fibrinolysis caused by the two types of plasminogen activator. The present study shows that changes in substrate composition (pH, ionic strength, fibrinogen concentration, plasminogen concentration) may influence to different degrees the fibrinolytic activities of human urokinase and the porcine tissue plasminogen activator. It is suggested, that this finding is partly related to marked differences in affinity for fibrin of the two activators.
A Technique for the Evaluation of Platelet-Collagen Adhesiveness in vitro
Authors: Aznar J. , Jimenez C. , Villa P.
Published: April 2009

A method for the evaluation in vitro of platelet-collagen adhesiveness has been developed. This method is based on counting platelets both before and after their contact with an insoluble collagen (IC) suspension. The results are expressed as adhesiveness index (AI). A number of variables which could influence the test has been evaluated and standardized in a way suitable for the routinary use of the technique described.
Coagulation Defect in Experimental Trypanosomial Infection
Authors: Essien E.M. , Ikede B.O.
Published: April 2009

Some coagulation parameters have been studied in animals experimentally infected with trypanosomial organisms (T.brucei or T.congolense). The partial thromboplastin time test with kaolin was regularly abnormally prolonged in all animals during infection. Although results of some coagulation factors in the intrinsic pathway cannot be used to explain this finding, it is suggested that the partial thromboplastin time test can be used as a test to monitor infection and recovery from this organism.
Heparin, Heparin-Activated Enzymes and Platelets
Authors: Ham J.M. , Lawrence J.C.
Published: April 2009

This review summarises evidence supporting the view that the therapeutic anticoagulant properties of heparin are related to its physiological function in the organism, especially its activation of lipoprotein lipase and lecithinase. The conflicting results obtained from studies of the effect of heparin on platelet function are discussed, together with reasons for these differences of opinion. Finally, a hypothesis which links heparin, heparin-activated enzymes and platelet function is proposed, this hypothesis being complementary to the current views concerning the activation by heparin of the inhibitor of activated factor X.
The Role of Factor XI in the Coagulant Activity of Platelets
Authors: Connellan J.M. , Castaldi P.A. , Muntz R.H.
Published: April 2009

Washed platelets were ruptured by freezing and thawing; a coagulant activity was released which would correct the clotting time of factor XI (FXI)-deficient plasma only in the presence of kaolin. Platelets from a FXI-deficient patient treated in a similar fashion also released a coagulant activity which could be absorbed onto Sepharose-heparin and eluted similarly to plasma FXI.Collagen was employed to induce a coagulant activity in platelet-poor plasma (PPP) and platelet-rich plasma (PRP) in the presence and absence of antibodies developed to purified FXI and FXII. The presence of FXII antibody had little effect on the activity induced in PRP. However, the presence of FXI antibody eliminated the difference between PPP and PRP. An activity was induced when FXI-deficient PRP was incubated with collagen and none with PPP. One type of collagen failed to induce a coagulant activity.
Studies on the Chemistry of Human Platelet Factor 4
Authors: Morgan F.J. , Chesterman C.N. , McGready J.R. , Begg G.S.
Published: April 2009

The chemical characteristics of several PF4 preparations have been examined by gel electrophoresis, amino acid analysis and NH2-terminal amino acid sequence determination. Preparations of PF4 from gel filtration and from affinity chromatography appeared identical. A single NH2-terminal sequence was determined as follows: NH2-Glu-Ala-Glu-Glu-Asp-Gly-Asp-Leu-Gln-SCMCys-Leu-SCMCys-Val-Lys-Thr-Thr-Ser-Gln-Val-Arg-. The molecular weight of the PF4 subunits, which seem to be identical, was 7,100 based on the recovery of NH2-terminal glutamic acid.
Activation of Plasminogen as a Feature in its Assay
Authors: Gaffney P.J. , Brasher M. , Lord K. , Kirkwood T.B.L.
Published: April 2009

Seven laboratories collaborating in a study of two intermediate purity plasminogen preparations (64/23, 63/6) observed that the amount of activator (urokinase or streptokinase) and the time of activation of plasminogen influenced the amount of plasmin generated. Using casein and a synthetic polypeptide (S-2251) as substrates, the authors subsequently showed that complete activation of plasminogen was difficult to achieve without activity losses due to plasmin autodigestion. Comparison of the polypeptide subunits (on SDS electrophoresis) of the various plasminogen activation mixtures with their plasmin activity allowed the conclusion that at maximum generation of plasmin from plasminogen, some plasminogen remains in the form of an inactive plasminogen intermediate (PLG-i).
Amidolytic Assay of Thrombin Bound to α2-Macroglobulin in Plasma
Authors: Musumeci V. , Landolfi R. , Bizzi B.
Published: April 2009

A method for the determination in plasma of α2-macroglobulin-bound thrombin is described. α2-Macroglobulin-bound thrombin is precipitated from plasma by 13% polyethyleneglycol, and its amidolytic activity is assayed by using the chromogenic substrate benzoyl-Phe-Val-Arg-p-nitroanilide (S 2160). After thrombin addition to plasma, only about 1.7 % of the added thrombin activity was recovered in the α2-macroglobulin precipitate. It is suggested that the contribution of α2-macroglobulin to the antithrombin activity of normal plasma is of little relevance.
Ditazole and Platelets
Authors: de Gaetano G. , Tonolli M.C. , Bertoni M.P. , Roncaglioni M.C.
Published: April 2009

Ditazole (4,5-diphenyl-2-bis-(2-hydroxyethyl)-aminoxazol) has been shown to be a strong in vitro inhibitor of human platelet aggregation brought about by release reaction inducers; in contrast, it did not significantly affect primary ADP-induced aggregation. Ditazole strongly inhibited the release of platelet-bound 14C-serotonin under the influence of Thrombofax, whereas it did not interfere with the transport and storage of serotonin in nonstimulated platelets. The effect of ditazole was not potentiated by acetyl-salicylic acid. Ditazole also inhibited ADP-reptilase clot retraction and modified thrombin-induced clot formation. The inhibition of platelet aggregation exerted by ditazole in plasma could be removed following gel filtration of platelets on Sepharose 2-B gel. This would indicate that ditazole does not act on platelets by a ‘hit and run’ mechanism.
Impaired Fibrin Formation in Advanced Cirrhosis
Authors: Dettori Anton Giulio , Ponari Oreste , Civardi Emilio , Megha Alessandro , Pini Mario , Potì Raffaele
Published: April 2009

The process of fibrin formation was systematically investigated in 25 patients with severe alcoholic cirrhosis. Results of functional tests are reported. A significant lengthening of the thrombin time was found which could not be completely attributed either to hypofibrinogenaemia or to an increase in physiological anticoagulants or to the presence of pathological antithrombins. A defect in fibrin polymerization was seen in the absence of significant levels of antipolymerizing agents. Indirect evidence pointed to an abnormal fibrinogen function. This was mainly suggested by the ‘polymerization curves’ of mixtures of normal and pathological plasmas and the changes in physico-chemical properties of the clot (optical and elastic properties; tensile strength). Altered synthesis in hepatocytes may lead to an ‘acquired dysfibrinogenaemia’ in the late stages of liver cirrhosis, although alteration of a normal fibrinogen molecule after secretion cannot be definitely excluded.
Clotting Factors and Platelets
Authors: Betterle C. , Fabris F. , de Marco L. , Del Prete G.F. , Girolami A.
Published: April 2009

Factor I (fibrinogen) and factor VIII were shown, by an indirect immunofluorescence technique, to be present in human washed platelets. In the case of fibrinogen, the immunofluorescent pattern had a ‘clod distribution’ up to a 1:128 dilution of the antiserum. Factor VIII showed a ‘speckled’ pattern up to the 1:64 dilution. Cross-absorption studies confirmed the presence of such factors. Factor II, VII, IX, X and XIII, however, were not found in washed platelets. A diffuse fluorescence was noted using normal rabbit sera, but this was due to a cross-reaction, since it disappeared using a 1:32 diluted sera.
Human Blood Platelet Elastase and Proelastase
Authors: Legrand Y. , Pignaud G. , Caen J.P.
Published: April 2009

After an in vitro incubation of platelets with fibrillar collagen, their elastase activity is markedly and rapidly increased while proelastase decreases: proelastase is activated in situ into elastase which is released in its active form from the platelet. The activation of proelastase is likely due to the action of a trypsin-like enzyme present in the platelet. This protease has the same type of localization as proelastase and elastase: their highest activity is associated with light granules but part of these enzymes (or precursor) is also associated with the membranes. The mechanism of the arterial elastolysis induced by the platelets probably involves their adhesion to intimal thrombogenic surfaces (collagen) followed by a reaction during which proelastase would become available to the trypsin-like enzyme and would be activated into elastase directly released in the vessel wall.
Ditazole and Platelets
Authors: de Gaetano G. , Cavenaghi A.E. , Stella L.
Published: April 2009

Ditazole (4,5-diphenyl-2-bis-(2-hydroxyethyl)-aminoxazol) is a new drug shown to inhibit prostaglandin release from rat platelets. The present study indicates that ditazole, at doses similar to those inhibiting prostaglandin formation in rat, inhibits in vivo collagen – but not ADP-induced rat platelet aggregation. In addition, ditazole does not prolong the bleeding time in rats, but even tends to shorten it. This effect could be due to the inhibition of prostaglandin formation at the side of the vascular injury produced to induce bleeding.
Generation of Coagulation Factors V, XI, and XII by the Isolated Rat Liver
Authors: Owen, jr. Charles A. , Bowie Walter
Published: April 2009

When isolated rat livers were perfused with platelet-free erythrocytes suspended in Tyrode’s solution containing 6% bovine serum albumin, the generation of factors V, XI, and XII was clearly demonstrable. On average, after 5 h of perfusion of a single liver, the concentrations in the perfusate (as a percentage of normal rat plasma) were about 6% for factor V, 8% for factor XI, and 5% for factor XII, compared with 20% for factor VII, which was used as the reference standard. When two livers were perfused, approximately twice these concentrations were achieved. When the properties of these factors in perfusate and plasma were compared, they agreed well except for differences in the celite adsorbability of factors XI and XII.
Some Characteristics of Various Fibrin Monomer Preparations Made from Dissolved Fibrin Clots
Authors: Brosstad F. , Godal H.C. , Kierulf P.
Published: April 2009

Fibrin monomers were made from dissolved clots according to three different methods [(1) method of DOnelly et al., using 1 m NaBr pH 5.2 as clot solvent; (2) method of Monelly-Berghaus et al., using 0.0167 m acetic acid to dissolve EDTA-clots; (3) method of Yudelman et al. using 3.3 m urea pH 7.4 as clot solvent]. The monomers were characterized by agarose gel chromatography, SDS-polyacrylamide gel electrophoresis (with and without reduction with 2-mercaptoethanol) and by acid polyacrylamide gel electrophoresis after sulfitolysis. Clottability and polymerization speed were compared to those of fibrinogen exposed to large amounts of thrombin (‘control monomers’). All preparations contained fibrin aggregates. These were of two different types, either non-covalently linked or covalently but not FSF-cross-linked aggregates. The latter type was probably due to -S-S- bonds, since they could be prevented by iodoacetamide. Methods 1 and 2 produced monomers which did not clot at all in buffer but clotted slowly in serum. Monomers prepared according to method 3 clotted even faster than did fibrinogen exposed to large amounts of thrombin. This was apparently due to the content of substantial amounts of covalently linked fibrin aggregates. When these were prevented by adding iodoacetamide under preparation, the monomers so produced had lower clotting speed than ‘control monomers’. From the present investigation it must be concluded that extrapolation of data obtained with fibrin monomers prepared from fibrin clots should be interpreted with great care.
Ditazole and Platelets
Authors: Mussoni L. , Poggi A. , Donati M.B. , de Gaetano G.
Published: April 2009

Ditazole (4,5-diphenyl-2-bis-(2-hydroxyethyl)-aminoxazol) inhibits in vivo platelet aggregation induced in mice by intravenous injection of cells derived from an experimental tumor, the Lewis lung carcinoma. Such a protective effect of ditazole could not be observed when the number of circulating platelets dropped slowly following intramuscular implantation and spontaneous dissemination of the same cancer cells. These results support previous observations suggesting a different mechanism for the thrombocytopenia observed after intravenous and intramuscular injection of cancer cells. Tail transection bleeding time of normal mice is significantly prolonged by ditazole, a finding at variance with that reported in rats.
Influence of Acetylsalicylic Acid and Paracetamol on Menstrual Blood Loss
Authors: Petruson Björn , Hahn Lennart , Korsan-Bengtsen Kristoffer , Hallberg Leif
Published: April 2009

In a double-blind cross-over study the influence of acetylsalicylic acid (ASA) and paracetamol on menstrual blood loss has been investigated in 23 women without an intrauterine loop or birth control pills. After intake of ASA there was no significantly, increased blood loss compared with intake of placebo or paracetamol.
Partial Purification of the Protein Moiety of Porcine Tissue Thromboplastin
Authors: Wijngaards G. , Hemker H.C. , van Deenen L.L.M.
Published: April 2009

The tissue thromboplastin activity of porcine lung was separated from an aqueous tissue extract by differential centrifugation. Repeated suspension and sedimentation yielded a thromboplastin preparation free of soluble protein. The most effective delipidation of the lyophilized preparation with minimum denaturation of the protein moiety of thromboplastin was achieved using n-heptane/n-butanol extraction. A detergent was required to solubilize the thromboplastin protein moiety from the delipidated preparation. Gel filtration in the presence of detergent permitted further delipidation of the protein moiety and yielded a purified protein moiety. Apparent homogeneity was observed for the purified protein with several fractionation techniques. This apparently homogeneous protein dissociates into the constituent proteins in the presence of dodecyl sulphate. The aggregation of proteins is ascribed to their hydrophobic nature. Gel filtration on Bio-Gel A-1.5 m was found to be useful in the separation of the dodecyl sulphate-protein complexes on a preparative scale. Following the removal of the dodecyl sulphate, the renaturation of the thromboplastin protein moiety was unsuccessful. The purified protein moiety with its low lipid content (1 %) is suitable for lipid requirement studies.
Variations in Blood Coagulation, Fibrinolysis, Platelet Function and Various Plasma Proteins during the Menstrual Cycle
Authors: Cederblad G. , Hahn L. , Korsan-Bengtsen K. , Pehrsson N.G. , Rybo G.
Published: April 2009

The variations in the number of platelets, platelet retention, blood coagulation, fibrinolysis and various plasma proteins were studied during the menstrual cycle in 30 normal women. Blood samples were taken on 6 occasions; day 1,2, and 3 of menstruation, day 5–9 (follicular phase), day 12–16 (around ovulation), and day 19–23 (luteal phase), respectively. The concentration of fibrinogen was lower during menstruation than in the luteal phase. Factor II-VII-X and platelet retention were lowest and the recalcification time was shortest during the menstruation. The number of platelets was highest in the ovulatory phase. The fibrinolytic activity was higher in the luteal phase and during the menstruation than in the follicular phase. The results might indicate an intrauterine clotting during the menstruation. The close correlations between the variations of most of the plasma proteins indicate the presence of some general not identified factor which is probably not the variation in the intravascular water content.
The Activated Factor X-Antithrombin III Reaction Rate: a Measure of the Increased Thrombotic Tendency Induced by Estrogen-Containing Oral Contraceptives in Rabbits
Authors: Gitel Sanford N. , Stephenson Ronald C. , Wessler Stanford
Published: April 2009

Estrogen-containing compounds are thrombogenic in man. The extent of thrombosis is dose-related, but a measure of this thrombogenicity is not currently available. Evidence is presented, using an animal model of venous thrombosis, that impaired Xa inhibitory activity (the rate of reaction between Xa and antithrombin III) correlates with the development of thrombosis initiated by thrombin in rabbits receiving an oral contraceptive compound. The responses in the clotting assay and in the extent of thrombosis are dose-related. The hypercoagulable state induced by oral contraceptives can be completely reversed by trace amounts of heparin.