bluuebunny/crossref_metadata_2025 huggingface dataset:
Femoral Artery Wall Morphology, Hemostatic Factors and Intermittent Claudication: Ultrasound Study in Men at High and Low Risk for Atherosclerotic Disease
Authors: Agewall Stefan , Wikstrand John , Wendelhag Inger , Tengborn Lilian , Fagerberg Björn
Published: April 2009

The aim of this study was to examine whether there was a relationship between ultrasound-assessed morphology of the femoral artery wall and hemostatic factors, and whether these factors were associated with intermittent claudication. One hundred and thirty men at high cardiovascular risk and 51 men at low risk were examined. The subjects (high- and low-risk) with moderate/large plaque (n = 96) had higher fibrinogen, thrombin/antithrombin complex and von Willebrand factor, compared to subjects with small/no plaque. The maximum intima-media thickness of the femoral artery was significantly associated with fibrinogen. These associations were independent of current smoking habits. Clinical atherosclerosis was associated with fibrinogen, von Willebrand factor, thrombin/antithrombin complex, plasminogen activator inhibitor activity, mean and maximum intima-media thickness and plaque status of the femoral artery. In conclusion, fibrinogen, von Willebrand factor and thrombin/antithrombin complex were related to plaque occurrence in the femoral artery. Clinical atherosclerosis was associated with fibrinogen, von Willebrand factor, thrombin/antithrombin complex and plasminogen activator inhibitor activity.
Tea Drinking and Haemostasis: A Randomized, Placebo-Controlled, Crossover Study in Free-Living Subjects
Authors: Vorster Hester , Jerling Johann , Oosthuizen Welma , Cummings John , Bingham Sheila , Magee Liz , Mulligan Angela , Runswick Shirley
Published: April 2009

The hypothesis that tea drinking may protect against coronary heart disease (CHD) through effects on clotting as measured by plasma fibrinogen, tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) was tested in 65 healthy volunteers (31 men and 34 women; aged 20-74 years) in a randomized, blind, placebo-controlled, crossover study lasting 10 weeks (run-in phase 2 weeks, tea and placebo phases 4 weeks). During the placebo phase, intakes of milk, sugar, water and caffeine were matched to those in the tea phase during which 6 mugs of tea were drunk daily. Compliance with tea intake was measured by marking tea bags with P-aminobenzoic acid and measuring recovery in 24-hour urine collections. The mean ± SD fibrinogen level, PAI-1 activity and tPA antigen level at baseline of 2.91 ± 0.81 g/l, 7.9 ± 5.3 U/ml and 4.76 ± 2.17 ng/ml, respectively, were in the normal range. No significant differences in these variables between the run-in, tea or placebo phases were observed. The putative protective effect of tea against development of CHD is not mediated through effects of black tea on fibrinogen, tPA or PAI-1.
The Changing Pattern of Venous Thromboembolic Disease
Authors: Cohen Alexander T. , Edmondson Robert A. , Phillips Michael J. , Ward Valerie P. , Kakkar Vijay V.
Published: April 2009

A review of 14,667 necropsy reports for every year from 1965 to 1990 and 6,436 diagnostic venograms performed from 1976 to 1990 was undertaken at a single teaching hospital. A progressive reduction in the percentage of necropsies reporting fatal pulmonary embolism from 6.1 to 2.1 %, occurred over the 25-year period (χ2 tests for linear trend with time p < 0.00001). Over the last decade, there has been a significant reduction in the rate of venographically diagnosed postoperative deep vein thrombosis (DVT) from 49.9 to 24.7 per 100,000 population (p < 0.0001) which was in marked contrast to the constant rate of non-postoperative DVT. Our findings suggest that the introduction of thromboprophylactic measures, in addition to changes in hospital practice, may have had a highly significant effect on the pattern of this serious, but potentially avoidable disease.
Haematology and Coagulation Indices in Paired Samples of Arterial and Venous Blood from Patients with Arterial Disease
Authors: Blann Andrew D. , Adams Rachel A. , Katai Freddy , Ashleigh Raymond , Taberner David A.
Published: April 2009

To investigate whether there are differences in haematology and coagulation indices in arterial and venous plasma, and whether those changes related to damage to the endothelium in atherosclerosis, we obtained blood samples from 22 subjects undergoing diagnostic angiography. There were no differences in any of the 15 routine haematological indices measured. There were no differences in prothrombin time, activated partial thromboplastin time, fibrinogen, tissue plasminogen activator, D-dimer, leucocyte elastase, soluble P-selectin or von Willebrand factor. In venous samples, von Willebrand factor was lower in serum than in plasma (p < 0.0001). Levels of the tissue plasminogen activator/plasminogen activator inhibitor-1 (tPA/PAI-1) complex were markedly higher in arterial blood than in venous blood (p = 0.004) and plasma viscosity was higher in venous blood (p = 0.0014). Consequently, with the exception of viscosity and the tPA/PAI complex, we can find no differences in arterial blood compared to venous blood which can contribute to the debate regarding the mechanism of damage to arterial endothelial cells but the relative protection of venous endothelial cells from injury in atherosclerosis.
Cerebral Prothrombotic State in Spontaneously Hypertensive Rats of Different Breeds
Authors: Oyama T. , Sasaki Y. , Okita N. , Giddings J.C. , Seki J. , Yamamoto J.
Published: April 2009

The thrombotic tendency in two breeds of spontaneously hypertensive rats (SHRs) was assessed by inducing occlusive thrombosis in pial blood vessels using a helium-neon laser method. A prothrombotic state was observed in the SHR of one breed as compared to the corresponding control WKY, but not in the other. Circulating platelet and erythrocyte counts and haematocrit values were significantly negatively correlated in arterioles with the number of laser pulses, which is an index of the thrombotic tendency, suggesting that the prothrombotic state was partly dependent on the counts of blood components. However, there was no correlation between the measured blood parameters and prothrombotic state in venules. The difference observed in arterioles and venules might be due to their differential haemodynamics and endothelial properties. Prothrombotic state in the SHR of one breed would be partly due to the much higher difference in blood components from its corresponding control compared to the comparatively less difference in the other breed.
Anticoagulant Effect of Unfractionated Heparin in Antithrombin-Depleted Plasma in vitro
Authors: Krulder J.W.M. , Strebus A.F. , Meinders A.E. , Briët E.
Published: April 2009

The aim of the study was to determine the effect of the antithrombin concentration on the anticoagulant response to heparin in vitro. Pooled plasma was depleted of antithrombin using heparin Sepharose. Unfractionated heparin (final concentration between 0 and 1 U/ml) was added to plasma with different antithrombin concentrations, and the activated partial thromboplastin time (APTT) was determined. Plasma with an antithrombin concentration over 0.27 U/ml shows a similar response to heparin as normal plasma; at lower levels the response is diminished. Even in plasma fully depleted of antithrombin, the APTT can be prolonged to a therapeutic level, although the amount of heparin needed is twice as high. At antithrombin concentrations over 0.27 U/ml, heparin is the major determinant of the anticoagulant effect.
Long-Term Use of the Low Molecular Weight Heparin Tinzaparin in Haemodialysis
Authors: Simpson H.K.L. , Baird J. , Allison M. , Briggs J.D. , Rowe P.A. , Welsh M. , Macdougall A.I. , Grant A.C. , Lowe G.D.O. , Rumley A. , Wallace M. , Menday A.P.
Published: April 2009

Fifty-two patients with chronic renal failure undergoing hospital haemodialysis were given a single bolus dose of tinzaparin (Innohep, Leo Laboratories, UK) into the arterial side of the dialyser, for up to 43 consecutive dialyses. The mean tinzaparin dose at the beginning was 2,139 IU anti-Xa and at the end 2,186 IU anti-Xa. Overall, tinzaparin proved a satisfactory anticoagulant for 1,370 (96.0%) out of 1,427 dialyses. Significant clot formation was prevented in 1,326 (92.8%) out of 1,429 dialyses. The clinically effective dose was associated with a mean plasma anti-Xa activity 1 h after dosing of 0.4 IU/ ml and suppressed fibrinopeptide A formation for up to 4 h. Bleeding, from the skin or mucous membranes, was recorded at 27 (1.9%) of 1,408 dialyses. Prolonged fistula bleeding on completion of dialysis was recorded on only 20 occasions. Other haemorrhagic events included haematemesis, bruising and subconjunctival haemorrhage (each in 1 patient) and epis-taxis (2 patients). Three patients died during the study of causes considered unrelated to tinzaparin therapy, myocardial infarction (2 patients) and multiple myeloma. Other adverse events reported included vomiting (3 patients) and hypotension (3 patients). Three patients ceased treatment due to haematemesis, prolonged bleeding from fistula puncture and thrombosis of the arteriovenous access, respectively. A small, but statistically significant, increase within the normal reference range was recorded in the mean values for aspartate aminotransferase and alanine aminotransferase.
Comparison of β-Thromboglobulin, Flow Cytometry, and Platelet Aggregometry to Study Platelet Activation
Authors: Matzdorff A.C. , Kemkes-Matthes B. , Voss R. , Pralle H.
Published: April 2009

This study compares granule membrane protein (GMP)-140 expression measured by flow cytometry, release of β-thrombo-globulin (β-TG), and platelet aggregometry as markers of platelet activation in vitro. Whole blood was activated with different concentrations of thrombin. There was a significant increase in β-TG plasma levels after stimulation with 0.01 and 0.04 U thrombin/ml. There was also an increase in GMP-140 expression, but interindividual variability was high. Aggregometry of platelet-rich plasma did not detect platelet activation and formation of platelet aggregates with 0.05 and 0.1 U thrombin/ml, while flow cytometry showed an early and significant increase of GMP-140 expression with these doses, β-TG release is a more sensitive marker of platelet activation than GMP-140 while flow cytometry is easier to perform and less susceptible to artifacts.
Subcutaneous Low-Molecular-Weight Heparin versus Standard Heparin and the Prevention of Thromboembolism in Medical Inpatients
Authors: Harenberg Job , Roebruck Peter , Heene Dieter L.
Published: April 2009

In a multicenter, double-blind clinical trial in 1,968 inpatients 1 daily subcutaneous administration of LMW heparin plus 2 placebo injections or 3 × 5,000 IU unfractionated (UF) heparin was given for 10 (8-11) days. The primary end point was the incidence of proximal deep-vein thrombosis or pulmonary embolism. Patients were assessed during the study period for development of proximal deep-vein thrombosis by compression sonography at days 1 and 10 and for pulmonary embolism by scintigraphy in symptomatic patients. Aim of the study was to demonstrate the equivalence of both treatment regimens. A total of 1,968 patients were randomized to receive UF or LMW heparin. Of these, 378 patients were excluded during the study period, so that 780 patients on UF and 810 on LMW heparin were included in the efficacy analysis. Four primary end points were observed with UF and 6 with LMW heparin, demonstrating the equivalence of treatments (p = 0.012). Additionally, pulmonary embolism was suspected as the cause of death in 6 patients who died during the study (3 per treatment group). A higher frequency of death (n = 32) was observed in the LMW-heparin group (p = 0.02) particularly documented in a part of the centers. Safety analysis showed a higher frequency of local pruritus, local erythema and subcutaneous hematoma, a higher increase in plasma levels of triglycerides, total cholesterol, alanine aminotransferase and aspartate aminotransferase, and a decrease of antithrombin III in patients receiving UF heparin. A decrease in platelet count (values ranging between 40,000 and 80,000/μl) was observed in 4 patients with UF and in none with LMW heparin. No severe thrombocytopenia was observed. Subcutaneous LMW heparin is as effective as UF heparin for prophylaxis of thromboembolism in bedridden, hospitalized medical patients.
A Recombinant Hirudin (IK-HIR02) in Healthy Volunteers
Authors: Schenk J.F. , Glusa E. , Radziwon P. , Butti A. , Markwardt F. , Breddin H.K.
Published: April 2009

The pharmacodynamic effects of different intravenous and subcutaneous doses of a recombinant hirudin (r-hirudin; IK-HIR02) on clotting parameters and bleeding time were investigated in 24 healthy volunteers in a bicenter study. Single intravenous bolus injections of 0.1, 0.2 and 0.3 mg/ kg IK-HIR02 caused a prolongation of thrombin time (TT) and aPTT in a dose-dependent manner and led to an increase in hirudin plasma levels& > 6 μg/ml. The plasma half-life of IK-HIR02 was calculated as 1.3 h. A continuous infusion of 0.03 mg/kg/h of IK-HIR02 for 4 h significantly prolonged TT and aPTT. At the end of the hirudin infusion, a mean plasma level of 0.19 ± 0.13 μg/ml was measured. Single subcutaneous doses of 0.1, 0.25 and 0.5 mg/kg markedly prolonged the coagulation tests. The highest increase in hirudin plasma levels was found 2 h after injection. At this time the aPTT was doubled after 0.5 mg/kg. After repeat subcutaneous injections of 0.3 mg/kg b.i.d., aPTT was doubled, and TT increased to about 200 s, 2 h after the injections. At this time the mean plasma level was 0.5-0.6 μg/ml. There was no cumulative effect after multiple injections. Bleeding time was not changed after the 4-hour intravenous infusion and after repeat subcutaneous injections of 0.3 mg/kg IK-HIR02. Bleeding time was moderately but significantly prolonged after the highest single intravenous and subcutaneous hirudin doses tested. Other than very minor local bleeding in some volunteers, IK-HIR02 was well tolerated. Biochemical blood and urine parameters did not change. In conclusion, r-hirudin (IK-HIR02) obtained by a new technique was well tolerated in healthy volunteers after single intravenous and subcutaneous injections, after repeat subcutaneous doses and during continuous intravenous infusion. Measurement of aPTT and anti-IIa activity, using a chromogenic substrate test, can be used to monitor hirudin effects if doses similar to those tested here are administered.
Protective Effects of Ticlopidine and Aspirin, Administered Alone and in Combination, on Thrombus Formation in Rat Cerebral Vessels
Authors: Sasaki Yasuto , Ishii Izumi , Giddings John C. , Yamamoto Junichiro
Published: April 2009

The protective effects of ticlopidine and d, l-lysine acetylsalicylate (L-ASA), used alone and in combination, on the pathogen-esis of thrombosis in cerebral blood vessels were investigated in a rat animal model using a He-Ne laser method. Ticlopidine and L-ASA, given orally at a concentration from 100 mg/kg, inhibited thrombus formation in a dose-dependent manner. Ticlopidine (300 mg/kg p.o.) inhibited thrombosis in arterioles and venules for 3 days after administration. The inhibitory activity of L-ASA (300 mg/kg p.o.) was less prolonged than that of ticlopidine and was observed for only approximately 24 h. Combined administration of ticlopidine and L-ASA significantly enhanced and prolonged the antithrombotic effects of either drug given alone. The results demonstrate that ticlopidine and L-ASA have potent antithrombotic properties in rat cerebral blood vessels in vivo.
Procoagulant Activity of Mononuclear Cells Is Increased in Myeloproliferative and Myelodysplastic Diseases
Authors: Bazzan M. , Vaccarino A. , Stella S. , Foli C. , Omedè P. , Gallone G. , Tamponi G. , Pileri A.
Published: April 2009

Procoagulant activity (PCA) of peripheral mononuclear cells (PMC) was evaluated in patients with primary thrombocythemia (PT, group A), polycythemia vera (PV), idiopathic myelofibrosis (IM) and myelodysplastic syndromes (group B), and in 15 healthy subjects as control group. PCA of PMC was assayed under basal conditions and after agonist-induced stimulation: bacterial lipopolysaccharide, glycosylated granu-locyte-macrophage colony-stimulating factor, recombinant α-interferon. PCA was similar in the control group and group A when no stimulation was used, while PCA was found significantly higher in group B patients in the same conditions. In group A patients and in the control group, but not in group B patients, a lower PCA expression was found when PMC were simultaneously coincubated with LPS and α-interferon with respect to LPS incubation alone.
Quantification of Hemostatic Proteins and Activation Products in Synovial Fluids from Arthritic Joints prior to and after Induction of Chemical Synoviorthesis
Authors: Römisch Jürgen , Krahl Ute , Hock Johann , Bläser Jörg , Fricke Reinhard , Maasjosthusmann Ulrich , Tschesche Harald
Published: April 2009

Synovial fluids drawn from joints of patients suffering from rheumatoid arthritis were investigated for their concentrations of proteins and activation markers of the complement, coagulation and fibrinolytic systems. A broad spectrum of plasmatic inhibitors and other hemostatic proteins were detectable by immunologic assays. Compared to normal plasma concentration ranges, levels of α2-antiplasmin, antithrombin III, heparin-cofactor II, factor H, α2-macroglobulin, inter-α-trypsin inhibitor, fibrinogen and particularly high molecular weight kininogen were found to be decreased when corrected for total protein content. However, highly elevated levels of C-reactive protein, factor XIII, PMN-elastase, prothrombin fragment F1+2 thrombin-antithrombin III, plasmin-antiplas-min and terminal complement-complexes as well as C5a were determined. Eight and 24 hours after induction of chemical synoviorthesis, a general increase in most of the parameters was observed. Statistically significant alterations were found for C1-inhibitor, factor H, α1-antitrypsin, inter-α-trypsin inhibitor, factor XIII, protein C, thrombin-antithrombin III complexes and C5a.
Influence of Recombinant Hirudin on Tissue-Factor-Induced Activation of Coagulation in Rabbits
Authors: Kouz Jalal , Czech Jörg , Nicolay Uwe , Dickneite Gerhard
Published: April 2009

Uncontrolled activation of the tissue-factor (TF)-dependent extrinsic pathway of coagulation can lead to severe impairment of the hemostatic balance. As thrombin plays the central role in the initiation of clotting, we used the highly specific thrombin inhibitor recombinant hirudin to prevent TF-induced coagulation activation in a rabbit model. Infusion of 0.5 μg·kg–1 •h–1 TF in rabbits for 7 h led to a decrease in fibrinogen and platelets, to an increase in fibrin monomers and to a prolongation of TT, aPTT and PT. Recombinant hirudin was administered in doses of 0.5, 1 and 2 mg·kg–1 body weight (intravenous bolus), the protocol included a pre-TF (recombinant hirudin given at t = 0) and a post-TF study group (recombinant hirudin given at t = 2 h after the start of the TF infusion). Fibrinogen plasma levels, platelet counts and recombinant hirudin plasma levels were measured at baseline (t = 0) at 0.5, 1, 2, 3, 4, 5, 6 and 7 h; the deceleration rate of fibrinogen and platelets per hour was calculated for the control and the recombinant-hirudin-treated groups. The deceleration rate for fibrinogen in the TF group was -0.227 g·1-1 •h–1 and was reduced by recombinant hirudin to -0.119, -0.116 and -0.095 g·1-1·h–1 for 0.5, 1 or 2 mg·kg-1, respectively (significant differences to control group, Jonck-heere-Terpstra test). The inhibitor similarly prevented the decrease of platelets dose-dependently. Recombinant hirudin was cleared from plasma with a terminal half-life of about 100 min; however, even after its clearance from plasma, recombinant hirudin significantly prevented the fibrinogen and platelet drop. Recombinant hirudin was effective when given in the pre-TF as well as in the post-TF phase.
A Recombinant Hirudin (IK-HIR02) in Healthy Volunteers
Authors: Schenk J.F. , Glusa E. , Radziwon P. , Butti A. , Markwardt F. , Breddin H.K.
Published: April 2009

The pharmacodynamic effects of different intravenous and subcutaneous doses of a new recombinant hirudin (IK-HIR02) on platelet adhesion, platelet-induced thrombin formation and on platelet count have been studied in 18 healthy volunteers in a bicenter study. Single intravenous bolus injections of 0.1, 0.2 and 0.3mg/kg IK-HIR02 in 6 volunteers caused a significant dose-dependent prolongation of platelet-induced thrombin generation time (PITT) and a significant inhibition of platelet adhesion to glass. Single subcutaneous doses of 0.1, 0.25 and 0.5 mg/kg IK-HIR02 slightly prolonged PITT and inhibited platelet adhesion to glass for up to 8 h. Repeat subcutaneous injections of 0.3 mg/kg IK-HIR02 b.i.d. in 6 healthy volunteers led to a prolongation of PITT and also to a reduction of platelet adhesion. In platelet-rich plasma (PRP) from blood samples which had been collected using hirudin as anticoagulant (0.7 μg/ml), the platelet count was constantly higher than in citrate PRP which had been sampled at the same time. The recombinant hirudin IK-HIR02 inhibits platelet adhesion to glass and also PITT. Both effects which have not been described before are most likely due to a direct inhibition of thrombin-induced platelet activation. These effects may contribute to the antithrombotic action of hirudin and probably have to be considered when hirudin is used in higher doses as an antithrombotic agent together with platelet function inhibitors to avoid excessive bleeding.
Comparison of Hemorrhagic Effect of Heparin and Human Activated Protein C with Use of Thrombostat 4000
Authors: Katsuura Yasuhiro , Tanabe Hirofumi , Kiyoki Mamoru , Funatsu Akinobu
Published: April 2009

The importance of bleeding as a complication of anticoagulant therapy is clearly recognized. We previously reported that amelioration of hemorrhage associated with disseminated in-travascular coagulation by the human activated protein C (APC) was greater than that by heparin. In this study, we compared the bleeding complication of intravenously administered APC and heparin in rabbits, and also estimated primary hemostasis. When both anticoagulants were intravenously infused, the bleeding time from a punctured ear vein was prolonged dose-dependently. However, at doses which prolonged the activated partial thromboplastin time nearly equally, the prolongation of bleeding was greater in heparin-administered rabbits. Blood withdrawn from heparin-administered animals showed increases in in vitro bleeding parameters which correlated with the in vivo bleeding time. However, only small changes were observed in the blood withdrawn from APC-administered animals. Both drugs induced either no change or only a slight decrease in the platelet count, hematocrit and fibrinogen content. These observations suggest that APC may be a more useful anticoagulant than heparin since it causes less bleeding tendency.
Relationship between Prothrombin Activation Fragment F1 +2 and Serum Cholesterol
Authors: Alessandri C. , Basili S. , Maurelli M. , Bracaglia D. , Andreozzi P. , Pergolini M. , Cordova C.
Published: April 2009

Plasma levels of fibrinogen, factor VIIc and prothrombin fragment F1+2, a marker of thrombin generation in vivo, were studied in 68 subjects with serum total cholesterol (TC) levels between 135 and 349 mg/dl but without clinical evidence of cardiovascular disease and other atherosclerotic risk factors. F1+2 plasma levels were directly correlated with TC (p < 0.0004), low-density lipoprotein cholesterol (LDL-C; p < 0.0018) and factor VIIc (p < 0.024). Thirty-five subjects with TC greater than 249 mg/dl (median value of the whole group) showed higher levels of Fl+2 (p < 0.0001) and fibrinogen (p < 0.0015) than those with TC lower than 249 mg/dl. In subjects with TC > 249 mg/dl and Fl+2 > 1.2 nM (median value of the whole group), a cholesterol-lowering drug (simvastatin) was able to reduce Fl +2 (p < 0.009) as well as TC and LDL-C. This study shows a relationship between serum cholesterol and the rate of thrombin generation supporting the hypothesis that a hypercoagulable state may occur in hypercholesterolemic subjects before the onset of clinical evidence of atherosclerotic cardiovascular disease.
Platelet-Derived Microparticles in Alloxan-lnduced Diabetes in Rabbits
Authors: Suzuki Masahiko , Kawakatsu Toshihiro , Miyake Tetsuya , Miyazaki Yasuhiko , Kagawa Hideo , Yanabu Mutsumasa , Nomura Shosaku , Fukuhara Shirou
Published: April 2009

To study platelet-derived microparticle generation in diabetes mellitus, we injected alloxan into male Japanese white rabbits. Injection of alloxan induced diabetes, but did not cause any significant change in various biochemical and hematological parameters. However, diabetic rabbits showed a significant elevation of platelet-derived microparticles from 8 weeks after alloxan injection (week 0: 0.45 ± 0.24%; week 8: 1.12 ± 0.61%, p < 0.005). These microparticles are known to have prothrombinase activity, suggesting that they may promote vascular complications in diabetes and may be used as a marker of vascular disease.
Large-Scale Screening for Factor V Leiden Mutation in a North-Eastern German Population
Authors: Schröder W. , Koesling M. , Wulff K. , Wehnert M. , Herrmann F.H.
Published: April 2009

Preliminary epidemiological data showed a high but varying prevalence of factor V Leiden mutation in various European populations. To analyze population differences statistically and generate reliable evaluation criteria for morbidity estimates, large numbers of unselected probands from different populations have to be tested. A convenient, efficient, reliable and cost efficient method for large-scale screening of factor V Leiden mutation has been developed using capillary blood samples soaked onto filter paper cards for the detection of mutations by heteroduplex analysis. Screening 1,628 alleles of a north-eastern German population by this procedure revealed an allele frequency of 3.56% (carrier rate 7.12%) which is significantly higher than those published for Italy and the Netherlands. Differences in allele frequencies compared to other European populations could statistically not be proved based on the small size of the published samples.
Anticoagulant Effects of Low-Molecular-Weight Heparin following Thrombolytic Therapy in Acute Myocardial Infarction: A Dose-Finding Study
Authors: Strandberg Lars-Erik , Kahan Thomas , Lundin Peter , Svensson Jan , Erhardt Leif
Published: April 2009

The aim of the present study was to gain clinical experience with different dose levels of dalteparin, a low-molecular-weight heparin, following thrombolytic therapy in acute myocardial infarction. Compared to heparin, dalteparin has a longer half-life and a greater and highly predictable bioavailability, which would suggest dalteparin to be a convenient alternative. Twenty patients with ECG signs of acute transmural myocardial ischemia received streptokinase (1.5 million IU for 60 min) and were allocated to a control group or to open treatment with 50, 75 or 100 IU of dalteparin/kg b.w. s.c. b.i.d., starting 4 h later, for 6 days. Each group consisted of 5 patients. Except for the control group, aspirin was withheld during dalteparin treatment. Anti-factor-Xa (anti-FXa) values increased dose-dependently during the first 24 h and were maintained throughout the study period. On day 6, anti-FXa levels after 100 IU/kg b.w. were 0.79 (0.59-1.00) IU/ml (median, min.-max.) 4 h after administration of dalteparin, and 0.51 (0.34-0.82) IU/ml before the subsequent dose of dalteparin. In conclusion, our results indicate that a dalteparin dose slightly higher than 100 IU/kg b.w. is required in order to obtain the presumed therapeutic range of anti-FXa (0.6-1.0 IU/ml).
Influence of Low Molecular Weight Hydroxyethyl Starch (HES 40/0.5-0.55) on Hemostasis and Hemorheology
Authors: Treib Johannes , Haass Anton , Pindur Gerhard , Grauer Markus T. , Seyfert Ulrich T. , Treib Wolfgang , Wenzel Ernst , Schimrigk Klaus
Published: April 2009

Hydroxyethyl starch (HES) with a high or medium molecular weight (MW) and a high degree of substitution is difficult to degrade and leads to an accumulation of large molecules. These molecules have a negative effect on hemostasiological parameters. In 10 patients with cerebrovascular diseases, a hemodilution therapy was carried out with low MW HES for 10 days. Due to the low MW of the HES used (56-61 kD), the rheological parameters erythrocyte aggregation and plasma viscosity were significantly lowered (p < 0.01). No coagulation parameters studied were affected beyond the dilution effect, which was measured using the decline in hematocrit. Low MW starch is a volume substitute that is well-suited for repeated infusion or hemodilution therapy, particularly for patients with increased hemorrhagic diathesis, because it does not affect hemostasis. The disadvantage of a relatively short volume effect can be compensated through a continuous infusion of a larger volume.
Differences in Platelet Count and Size between Marrow and Peripheral Blood
Authors: Aliberti Giuseppe , Proietta Maria , Pulignano Isabella , De Franceschi Lucilla
Published: April 2009

Automatized platelet parameters were evaluated in 23 unselected patients undergoing a bone marrow examination for diagnostic purposes, both in medullary and in peripheral blood, with the aim of investigating the biological significance of platelet volume heterogeneity. In the marrow blood the platelet count was 10.07 ± 21.25% (p < 0.05) lower and the platelet volume 7.93 ± 6.88% (p < 0.001) higher compared to peripheral venous blood: 275,173 ± 108,079 versus 296,652 ± 104,814/mm3 (p < 0.05) and 8.93 ± 1.46 versus 8.23 ± 1.57 f1 (p < 0.001), respectively. The same behavior was observed between the marrow and the arterial blood collected from 12 out of the 23 patients, while no significant difference was observed between arterial and venous blood. The differences observed might be attributable to a platelet population replacement under homeostatical regulation and seem to support the concept that the large platelets are younger elements.
Tissue Plasminogen Activator and Plasminogen Activator Inhibitor Status in Budd-Chiari Syndrome
Authors: Dayal Sanjana , Pati Hara Prasad , Sharma Mahesh Prakash
Published: April 2009

Alterations in the plasma levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) as observed in various liver disorders are attributed to deranged liver function. Status of these parameters in patients with Budd-Chiari syndrome (BCS) has not been reported so far. In the present study 27 patients with BCS with hepatic and/or inferior vena cava occlusion were investigated for any defect in the fibrinolytic system. Mild to moderately deranged liver function tests were observed in all (except 2) patients. Three patients each showed mildly increased levels of t-PA (3/27) and PAI-1 (3/27). The levels of t-PA and PAI-1 however did not show any correlation with liver function parameters.
A Mathematical Model of Coagulation Factor VIII Kinetics
Authors: Noe Dennis A.
Published: April 2009

It appears that the binding of coagulation factor VIII to von Willebrand factor in plasma stabilizes the otherwise highly labile factor VIII. A mathematical model of factor VIII kinetics has been developed based upon this proposed effect of factor VIII binding. The model’s kinetic parameter values have been estimated by fitting the model to data available in the medical literature. The model gives accurate quantitative predictions of the elevated steady-state concentrations of factor VIII in clinical conditions associated with the acute phase reaction and in pregnancy, the decreased steady-state concentrations of factor VIII in females heterozygous for hemophilia, the decreased steady-state concentrations of factor VIII in patients with type 1 (heterozygous) and type 3 (homozygous) von Willebrand disease, and the variable half-life of factor VIII in factor replacement therapy for hemophilia and von Willebrand disease.
Coagulopathy of Childhood Nephrotic Syndrome – A Reappraisal of the Role of Natural Anticoagulants and Fibrinolysis
Authors: Al-Mugeiren M.M. , Gader A.M.A. , Al-Rasheed S.A. , Bahakim H.M. , Al-Momen A.K. , Al-Salloum A.
Published: April 2009

In an attempt to characterise further the coagulopathy of childhood nephrotic syndrome, this study concentrates on simultaneous measurements of the natural anticoagulants [antithrombin III (ATIII), proteins C and S] and the fibrinolytic factors, tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI). The study groups consisted of 41 children (ages ranging from 2 to 14 years; median 7.1) in the relapse of nephrosis and 48 children (ages ranging from 3 to 14 years; median 7.6) in remission. The results obtained were compared with normal values obtained in healthy age- and sex-matched controls (n = 103). During relapse, there was a marked increase in the plasma level of fibrinogen, protein C, and protein S and reduced plasma ATIII level; tPA level was similar to control but PAI level exhibited a significant reduction. During remission, the protein C level either remained elevated or increased further, but some decreased. Protein S and plasma ATIII level normalised. The fibrinolytic activator tPA dropped slightly but the PAI level remained significantly below control levels. We conclude that in the relapse of childhood nephrosis, despite the existence of a significant prothrombotic tendency as featured by hyperfibrinogenaemia and markedly reduced ATIII level, the simultaneous elevation of the natural anticoagulant, protein C level and enhanced fibrinolysis that persist until the remission phase, seem to be major preventive mechanisms guarding nephrotic children against thromboembolic phenomena.
Prostanoid Production in the Presence of Platelet Activation in Hypoxic Cocaine-Treated Rats
Authors: Togna G. , Graziani M. , Sorrentino C. , Caprino L.
Published: April 2009

To extend our previous in vitro data, we investigated the effects of cocaine on thromboxane A2 (TXA2) and prostacyclin (PGI2) production in vivo in the rat. To obtain the slight platelet activation that our in vitro experiments showed useful to highlight the effect of cocaine, we infused cocaine in rats in the presence of platelet-activating factors (circulation of blood through a perspex vascular device or by infusion of sodium arachidonate) and in various respiratory conditions. Experiments were conducted in rats breathing atmospheric air (nor-moxic conditions) and in rats breathing an oxygen-poor mixture (hypoxic conditions). In rats under hypoxic conditions cocaine invariably increased TXA2 plasma levels, whereas in normoxic conditions it increased TXA2 only in the presence of platelet-activating factors. Cocaine significantly increased PGI2 plasma levels in arachidonate-treated rats in hypoxic respiratory conditions; in normoxic conditions cocaine left PGI2 levels unchanged. These results support the hypothesis that in cocaine users who have concomitant pathological conditions able to activate platelets, such as atherosclerosis, coronary vasospasm or ischaemia, or both, cocaine may contribute to the onset of thrombotic phenomena by interfering with the prostaglandin system.
Cells and the Activation of Factor VII
Authors: Rao Vijaya Mohan , Rapaport Samuel I.
Published: April 2009

Binding of factor VII to tissue factor (TF) present on or released from cells initiates TF-dependent coagulation in vivo. Earlier data obtained with relipidated TF suspensions led to the hypothesis that all factor VII bound to limiting TF sites exposed after tissue injury could be rapidly activated to Vila/ TF complexes by low concentrations of factor Xa, IXa, and Vila. However, newer data on the activation of factor VII bound to TF expressed on cultured cell monolayers support the hypothesis that not all VII/TF complexes formed at a site of tissue injury are readily activated to VIIa/TF complexes during hemostasis. This is possibly related to why recombinant factor Vila can bypass impaired IXa/VIIIa/phospholipid complex function in hemostasis.
Monocyte/Macrophage Regulation of Coagulant Events
Authors: Tracy Paula B. , Allen Debra H. , Worfolk Laura A. , Lawler Royce Robinson
Published: April 2009

Monocytes/macrophages actively regulate both the assembly and function, as well as the substrate specificity, of various coagulation enzymes at their membrane surface. Regulation is effected through a variety of mechanisms, not limited to, but including the expression of receptors (or ‘binding sites’) for the various protein constituents of the complexes, the expression of different receptors which may alter the function of the protease, and the expression of membrane proteases which may affect protein cofactor function. Monocyte stimulation with various agonists modulates many of these responses as does their adherence to and differentiation on various substrates.
Cellular Interactions in Hemostasis
Authors: Hoffman Maureane , Monroe Dougald M. , Roberts Harold R.
Published: April 2009

Coagulation reactions normally occur on cell membranes in vivo. Using a cell-based in vitro model system, we have shown that where a factor is located, not simply how much is activated, is critically important in determining its role in hemostasis. Factor Xa activated on a tissue factor (TF)-bearing cell is not equivalent to factor Xa activated on a platelet surface. Factor IX and factor VIII are required for hemostasis because they combine to generate factor Xa on the platelet surface. Factor X activation by factor VIIa/TF does not compensate for a lack of factor IX or VIII because the factor Xa activated by VIIa/TF is located on the wrong surface for efficient thrombin generation.
Regulation of Tissue Factor Gene Expression in Human Monocytic and Endothelial Cells
Authors: Mackman Nigel
Published: April 2009

Tissue factor (TF) is inducibly expressed within the vasculature by monocytes and endothelial cells. Transcriptional activation of the TF gene in these two cell types by bacterial lipopolysaccharide (LPS) or cytokines appears to be regulated by a common mechanism. Functional studies identified a 56-bp LPS response element which contains two AP-1 sites and a kB site. Assembly of a multiprotein complex composed of Fos-Jun and c-Rel-p65 heterodimers is required to induce TF gene transcription. Inhibiting proteolytic degradation of IκBα prevents nuclear translocation of c-Rel-p65 heterodimers and blocks inducible TF expression in monocytic and endothelial cells.
The Tissue Factor-Factor VII Complex: Recent Advances towards Elucidating the Structure and Function of the Initiator of Haemostasis
Authors: Tuddenham E.G.D.
Published: April 2009

Localised extravascular initiation of mammalian haemostasis is achieved by the anatomical localization of tissue factor (TF) around blood vessels and at organ surfaces. TF avidly binds factor VII from outflowing blood following vascular injury, forming the tissue factor/factor VII (TF.VII) complex. This is rapidly converted to TF.VIIa, the active initiator of blood coagulation. Structural studies have revealed that the extracellular region of TF consists of two C2-type immunoglobulin-like modules rigidly held at an angle of 125° by an extensive buried interface. The regions of TF involved in binding factor VII extend from the binding finger of the domain interface across quite a wide surface of the distal (N-terminal) module. Solution scattering studies show that both TF and factor VII adopt an extended conformation in solution and that the complex is formed by a compact side by side alignment of the two proteins along their long axes.
Influence of the γ-Carboxyglutamic Acid-Rich Domain and Hydrophobic Stack of Factor Vila on Tissue Factor Binding
Authors: Persson Egon
Published: April 2009

Des(1-38)- and des(1-44)-factor Vila (fVIIa) were inhibited with Phe-Phe-Arg-chloromethyl ketone (FFR-cmk). Des(1-38)-FFR-fVIIa inhibited tissue factor (TF)-enhanced fVIIa amidolytic activity with an IC50 value of 15 nM, whereas 3-and 6-fold higher values were obtained with des(1-44)-FFR-fVIIa using soluble and full-length TF, respectively. The value for FFR-fVIIa was 8-10 nM. Clotting time was prolongated with IC50 values for inactivated des(1-38)- and des(1-44)- fVIIa of 50 nM and 1 μM, respectively, whereas FFR-fVIIa yielded a value of 10 nM. From binding experiments in a BIA-coreTM instrument, dissociation constants for the complexes between TF1-218 and fVIIa, des(1-38)-fVIIa and des(1-44)- fVIIa of about 3, 20 and 70 nM, respectively, could be estimated.
Factor VIla-Tissue Factor Interactions: An Evaluation Using Factor VII-actor IX Chimeras
Authors: Chang Jen-Yea
Published: April 2009

Using molecular biological techniques, a series of factor VII-factor IX chimeric molecules were made for both kinetic and competition binding assays to tissue factor in order to understand the interaction between factor VIla and tissue factor. The results of the binding studies indicated that the major interaction between factor Vila and tissue factor involved both the first epidermal growth factor-like (EGF1) and catalytic domains of factor VII. In addition, both the γ-carboxyglutamic acid-containing (Gla) and EGF2 domains also play a minor role in binding to tissue factor. The Gla and EGF-2 domain might either impart structure to the rest of the molecule or contribute a relatively small amount of energy to direct binding.
Effect of Ca2+ on the Structure and Function of Factor VIla
Authors: Petersen Lars C. , Persson Egon
Published: April 2009

Binding of Ca2+ to factor VIla is required for its binding to phospholipids, tissue factor, and for obtaining full amidolytic activity. This presentation describes various binding studies performed with recombinant factor VIla and fragments hereof in order to localize Ca2+ sites and obtain a better understanding of the functional implication of Ca2+ binding to these sites. Results obtained by means of Ca2+-dependent monoclonal antibodies, immunosorbent assays, intrinsic protein fluorescence and terbium luminescence technique are described and the results are interpreted in terms of a putative model.
Effect of Ca2+ on the Structure of Vitamin K-Dependent Coagulation Factors
Authors: Sunnerhagen Maria , Drakenberg Torbjörn , Forsén Sture , Stenflo Johan
Published: April 2009

Coagulation factors VII, IX, X, and protein C contain an N-terminal module with 9-12 γ-carboxyglutamic acid (Gla) residues. It is followed by two modules that are homologous to the epidermal growth factor (EGF) and a C-terminal serine protease module. Upon calcium binding to the Gla module the side chains of three hydrophobic residues are exposed in a manner indicating that they interact with biological membranes. The calcium-binding site in the first EGF-like module appears to be required for proper orientation of the Gla and EGF-like modules relative to each other. A single calcium-binding site is also present in the serine protease module. The properties of these calcium-binding sites are briefly reviewed.
Computational Studies of Human Prothrombin Fragment 1 the Gla Domain of Factor IX and Several Biological Interesting Mutants
Authors: Li Leping , Darden Tom , Hiskey Richard , Pedersen Lee G.
Published: April 2009

We have employed molecular dynamics simulations to understand the properties of the γ-carboxyglutamic acid (Gla) domains of human prothrombin fragment 1 (residues 1-144) and factor IX (residues 1-47). The simulations are based on (1) the crystal structure of bovine prothrombin fragment 1 in the presence of calcium and (2) our subsequent simulation of the solution structure for which we found accommodation of the long range ionic forces critical. In addition, we have estimated the solution structures for key mutant proteins [prothrombin (Gla6 to Asp and Gla 16 to Asp) and factor IX (Gly12 to Ala)]. The simulations for the latter two mutants do not stabilize, a result in concert with the known biological data.
P-Selectin Induction of Tissue Factor Biosynthesis and Expression
Authors: Furie Bruce , Furie Barbara C.
Published: April 2009

P-selectin on activated platelets and stimulated endothelial cells mediates cell adhesion with monocytes and neutrophils. Since activated platelets induce tissue factor on monocytes, we examined the effect of P-selectin on this activity. Chinese hamster ovary cells expressing P-selectin stimulated tissue factor activity in purified monocytes whereas untransfected Chinese hamster ovary cells and CHO cells expressing E-selectin did not. Anti-P-selectin antibodies inhibited these effects. Incubation of CHO:P-selectin with monocytes stimulates tissue factor mRNA development and the expression of tissue factor antigen on the monocyte surface. These results indicate that P-selectin upregulates the expression of tissue factor on monocytes.
Determinants of Coagulation Activation in Humans
Authors: Bauer Kenneth A. , Eichinger Sabine , Mannucci Pier M. , Rosenberg Robert D.
Published: April 2009

To evaluate the mechanism responsible for the generation of factor VIla in vivo, we measured the levels of this enzyme after administering purified factor IX concentrates to patients with hemophilia B. Their factor VIla levels were initially very-low and gradually increased to normal, but there were no significant changes in the generation of factor Xa or thrombin. The administration of 10 μg/kg body weight of recombinant factor Vila to patients with factor VII deficiency increased the circulating levels 35-fold, but this only resulted in normalization of the activation of factor IX and factor X. Our data indicate that factor IXa is primarily responsible for the basal levels of free factor Vila in vivo, and that changes in free factor Vila in the blood do not necessarily lead to alterations in factor X activation.
Antithrombotic and Antilesion Benefits without Hemorrhagic Risks by Inhibiting Tissue Factor Pathway
Authors: Harker Laurence A. , Hanson Stephen R. , Wilcox Josiah N. , Kelly Andrew B.
Published: April 2009

The effects of inhibiting tissue factor-dependent thrombus formation on vascular neointimal lesion formation have been evaluated by inhibiting tissue factor activity using intravenous injections of active-site inactivated recombinant factor VIla (FVIIai) administered to baboons immediately prior to initiating bilateral femoral balloon artery angioplasty and surgical carotid endarterectomy. FVIIai abolished thrombus formation at sites of vascular injury and decreased vascular lesion formation by approximately 50 percent at 30 days. We conclude that thrombus formation at sites of vascular injury is predominately tissue factor-dependent and that transient inhibition of tissue factor activity prevents both vascular thrombosis and vascular lesion formation, which implies that transiently inhibiting tissue factor at the time of elective mechanical vascular procedures may be useful in reducing clinical restenosis.
Inhibition of Tissue Factor and Cytokine Release
Authors: Gray Elaine , Thomas Stephen , Mistry Yogesh , Poole Stephen
Published: April 2009

The effect of inhibitors of cytokine release and plasma coagulation on lipopolysaccharide (LPS)-indueced tissue factor and interleukin-6 (IL-6) was investigated. Dexamethasone, an inhibitor of cytokine production, inhibited LPS-induced tissue factor and IL-6 release by mononuclear cells (MNC), but enhanced IL-1β-evoked tissue factor activity. Clinical antithrombin (AT) concentrates inhibited, in a dose-dependent manner, tissue factor and IL-6 production by MNC and human umbilical vein endothelial cells (HUVEC). The three AT preparations tested, when compared using the same antithrombin unit, had different potencies. Activated protein C (APC) augmented LPS stimulation of HUVEC and further increased the production of tissue factor and IL-6. The same effect was not observed with MNC; LPS-induced tissue factor and IL-6 release were unaffected by APC. Truncated tissue factor pathway inhibitor (TFPI1-161) inhibited LPS-induced MNC tissue factor and IL-6 production, but was unable to prevent LPS stimulatory activity on HUVEC. These data suggest a complex interaction between the coagulation pathway and the cytokine network.