bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Thrombin Activatable Fibrinolysis Inhibitor (TAFI) Contribute to Impairment of Fibrinolysis in Patients with Preeclampsia and/or Intrauterine Fetal Growth Retardation?
Authors: Hamad R. , Antovic A. , Blombäck M. , Bremme K. , Antovic J.P.
Published: March 2018

Thrombin Activatable Fibrinolysis Inhibitor (TAFI) is a relatively recently described glycoprotein (MM 55 KDa) that can be converted into its active form by the thrombin/thrombomodulin complex and potentially inhibits fibrinolysis. Since it represents a link between coagulation and fibrinolysis, TAFI can be expected to play a part in various clinical conditions associated with a thrombotic tendency. Preeclampsia (PE) and intrauterine fetal growth retardation (IUFGR) are fairly common complications of pregnancy that are characterized by hemostatic abnormalities. TAFI antigen and its influence on hemostasis was investigated in 46 women with PE and/or IUFGR and in 16 normal pregnancies. We found a significant decrease of TAFI antigen in the patient group. Using the recently described method Overall Hemostatic Potential (OHP) in plasma, we measured clot lysis time (CLT) and overall fibrinolytic potential (OFP). We found that CLT is prolonged and OFP decreased in patients with PE and/or IUFGR. Since OFP did not increase after addition of the specific inhibitor of TAFI (potato tuber carboxypeptidase inhibitor), it seems that TAFI does not contribute to the impairment of fibrinolysis in these patients. Since serum albumin was decreased together with presence of proteinuria and aminotransferases were increased in the patients, it seems that one explanation for the decrease in TAFI could be reduced hepatic synthesis and an increased loss in urine. It can be speculated that this mechanism can prevent more serious thrombotic complications in patients with PE and/or IUFGR.
Patients with Coronary Artery Disease who Present with Chest Pain Have Significantly Elevated Platelet Contractile Force and Clot Elastic Modulus
Authors: Krishnaswami Ashok , Jesse Robert L. , Kontos Michael C. , Minisi Anthony J. , Ornato Joseph P. , Vetrovec George W. , Martin Erika J. , Carr Marcus E.
Published: March 2018

Rapid laboratory markers that correlate with patient risk would facilitate the decision making regarding admission of patients with chest pain (CP). Platelet contractile force (PCF) and clot elastic modulus (CEM) are elevated in patients undergoing coronary bypass grafting. This study assessed PCF, CEM, and platelet aggregation in patients presenting to the emergency department with chest pain (CP). Results were compared with fifty normal controls. Both the total group of CP patients (n = 100) and the subset of patients (n = 36) with documented coronary arterys disease (CAD) had significantly elevated PCF and CEM, and significantly decreased platelet aggregation relative to normal (p <0.001 for the total group, p <0.008 for patients with CAD). Patients with electrocardiographic evidence of ischemia had the highest PCF and CEM values of any patient group. Increased PCF and CEM were not due to higher platelet counts, and PCF did not differ by race.
Hemophilia A Mutations within the Factor VIII A2-A3 Subunit Interface Destabilize Factor VIIIa and Cause One-stage/ Two-stage Activity Discrepancy
Authors: Hakeos William , Miao Hongzhi , Sirachainan Nongnuch , Kemball-Cook Geoffrey , Saenko Evgueni , Kaufman Randal , Pipe Steven
Published: March 2018

Thrombin-activated factor VIII (FVIIIa) is a heterotrimer with the A2 subunit in a weak ionic interaction with the A1 and A3-C1-C2 subunits. Dissociation of the A2 subunit correlates with inactivation of FVIIIa. A homology model (Blood 89:2413, 1997) of the triplicated A domains of factor VIII (FVIII) predicts a pseudo-threefold axis at the tightly packed hydrophobic core with several interdomain interactions. These lie at the interface of A1-A2, A2-A3 and A1-A3. We have previously demonstrated that hemophilia A mutations (R531H, A284E, S289L) within the predicted A1-A2 and A1-A3 interface disrupt potential intersubunit hydrogen bonds and have the molecular phenotype of increased rate of inactivation of FVIIIa due to increased rate of A2 subunit dissociation. Patients with these mutations exhibit a clinical phenotype where the FVIII activity by one-stage(1-st) assay is at least two-fold higher than by two-stage(2-st) assay. We have now also explored mutations within the predicted A2-A3 interface (N694I, R698W and R698L) that also have the phenotype of 1-st/2-st activity discrepancy. These mutations exhibit the same molecular mechanism of increased instability of FVIIIa as those mutations described along the A1-A2 and A1-A3 interfaces. This suggests that the entire tightly packed hydrophobic core within the predicted pseudo-threefold axis contributes to stabilization of FVIIIa.
Association Between Increased Homocysteine Levels and Impaired Fibrinolytic Potential: Potential Mechanism for Cardiovascular Risk
Authors: D’Agostino Ralph , Jacques Paul , Bostom Andrew , Wilson Peter , Lipinska Izabela , Mittleman Murray , Selhub Jacob , Tofler Geoffrey
Published: March 2018

Elevated homocysteine levels increase cardiovascular risk although the mechanism is not well understood. Since thrombosis plays an important role in plaque development and acute coronary syndromes, hyperhomocysteinemia may increase risk by increasing the thrombotic potential.

Hemostatic risk factors were measured in 3216 individuals (1451 men and 1765 women) free of cardiovascular disease who participated in cycle 5 of the Framingham Offspring Study. An increase in homocysteine level was associated with a rise in plasminogen activator inhibitor (PAI-1), tissue plasminogen activator (TPA) antigen, von Willebrand factor and fibrinogen level. After regression analyses adjusting for covariates, there remained significant associations between homocysteine and PAI-1 and TPA antigen.

Increasing homocysteine levels are associated with impaired fibrinolytic potential, as indicated by increased PAI-1 and TPA antigen levels. These data suggest that folic acid and other homocysteine lowering therapies may decrease cardiac events through a reduction in thrombotic tendency.
Should Patients with Deep Vein Thrombosis Alone be Treated as Those with Concomitant Asymptomatic Pulmonary Embolism? A Prospective Study
Authors: Büller Harry , Lensing Anthonie , Bonet Montserrat , Roncales Javier , Muchart Jordi , Fraile Manuel , Monreal Manuel
Published: March 2018

The established initial treatment of patients with deep vein thrombosis (DVT) or pulmonary embolism (PE) consists of the administration of subcutaneous, weight adjusted, low-molecular weight heparin (LMWH). However, the use of the same LMWH dosages for patients with either DVT or PE is not supported by data from comparative studies.

1,000 consecutive patients with acute, proximal DVT were prospectively evaluated. All patients underwent a ventilation-perfusion lung scan on admission, and remained in hospital for at least 7 days. Patients with silent PE received once daily 10,000 to 15,000 IU subcutaneous LMWH dalteparin according to body weight for 7 days, and then vitamin K antagonists. Patients with DVT alone received LMWH in a fixed dose of 10,000 IU once daily for at least 5 days, and then vitamin K antagonists. The rate of both, major bleeding and symptomatic PE episodes during the 7-day study period was evaluated.

Thirteen patients (1.3%) developed recurrent PE (1 died) and 16 patients (1.6%) had major bleeding (7 died). Recurrent PE was significantly more common in patients with silent PE (9 of 258 patients, 3.5%) than in those with DVT alone (4 of 742 patients, 0.5%. Odds ratio: 6.5; p <0.001). There were no significant differences in bleeding rate between patients with silent PE and those with DVT alone. However, the use of a fixed 10,000 IU dose in patients with DVT alone led to a significantly lower bleeding rate in patients weighing over 70 kg: 1 of 349 patients (0.3%) as compared to 9 of 393 patients (2.3%) in those weighing less than 70 kg (odds ratio: 0.12; p = 0.018).

Fixed-dose 10,000 IU of LMWH dalteparin once daily proved to be both effective and safe in patients with DVT alone. The observed recurrence rate of 0.5% in these patients compares favourably with the 3.5% rate in patients with silent PE. Furthermore, this fixed-dosage was also safe. Patients weighing over 70 kg had a significant decrease in the rate of major bleeding, and no compensatory increase in the rate of recurrent PE.
Combined Activation of Coagulation and Inflammation has an Important Role in Multiple Organ Dysfunction and Poor Outcome after Severe Trauma
Authors: Kameue Takashi , Matsuda Naoyuki , Hayakawa Mineji , Ishitani Toshiteru , Morimoto Yuji , Kemmotsu Osamu , Gando Satoshi
Published: March 2018

We tested the hypothesis that activated neutrophil-endothelial cell interaction in DIC can cause endothelial injury contributing to multiple organ dysfunction syndrome (MODS) and a poor outcome after trauma. Fifty-eight severe trauma patients, 29 with DIC and 29 without DIC were studied. Serial levels of soluble L-, P-, and E-selectins, ICAM-1, VCAM-1, thrombomodulin, and neutrophil elastase were measured on days 0-4 after trauma. The numbers of systemic inflammatory response syndrome (SIRS) criteria that patients met were determined, simultaneously. In the DIC patients, higher DIC scores, lower platelet counts, and a longer duration of SIRS were found compared with the non-DIC patients. The incidence of ARDS and MODS were higher in patients with DIC than in those patients without DIC, and the DIC patients had poor outcome. Soluble L-selectin (sL-selectin) level on Day 1 in the DIC patients who died was markedly lower than those in the non-DIC patients. The levels of sPand sE-selectins, sICAM-1, and sVCAM-1 were more elevated in the patients with DIC than in those without DIC on days 2 to 4. Neutrophil elastase and sThrombomodulin levels in the DIC patients persistently increased during the study period compared to those in the non-DIC patients. Maximum DIC scores in the DIC group showed good correlations with peak levels of sICAM-1, sVCAM-1, neutrophil elastase, sThrombomodulin, and the number of dysfunctioning organs. Highly activated and sustained inflammation caused by neutrophil-endothelium interaction in DIC gives rise to MODS and poor outcome in patients with severe trauma. These results suggest a close relationship between inflammation and thrombosis in posttrauma DIC.
Arterial Intima-Media Thickness and its Relationship with Cardiovascular Disease and Atherosclerosis: A Possible Contribution of Medium-Sized Arteries
Authors: Šrámek A. , Reiber J. H. C. , Rosendaal F. R. , Bucciarelli P.
Published: March 2018

The intima-media thickness (IMT) of the arterial wall, measured by B-mode ultrasonography, has been related to cardiovascular disease and atherosclerosis in many studies, most of which have considered carotid and common femoral arteries. No study has related the IMT of medium-sized arteries (e.g. brachial) to the atherosclerotic process. The aim of this study was to evaluate whether more peripheral arteries (e.g. brachial, superficial femoral and popliteal) represent a good model in studies of arterial wall IMT, as well as carotid artery. Twenty-six male patients with demonstrated coronary artery disease (median age 63 yrs; range 41–70) and twenty-four male controls (median age 62 yrs; range 53–74) were studied. The far-wall IMT of the common carotid, brachial, superficial femoral and popliteal arteries was measured by high-resolution B-mode ultrasonography. Its relationship with ischemic cardiovascular disease and the presence of atherosclerotic plaques in all the arteries was also evaluated. Mean IMT values were higher in patients than controls, more so in superficial femoral artery (IMT difference 0.08 mm [95% confidence interval 0.02 – 0.14]) and popliteal artery (0.08 [0.01–0.15]) than in common carotid artery (0.02 [−0.070.11]) or brachial artery (0.01[−0.01–0.03]). The difference did not change after adjustment for age. The prevalence of plaques was consistently higher in patients than controls, except for brachial artery, in which no plaque was found either in patients and controls. In all the arteries except brachial we found an association between increase in IMT and number of plaques. Age was strongly related to the presence of plaques in the carotid artery, and less markedly in superficial femoral and popliteal arteries.

The brachial artery does not seem a good model to study atherosclerosis by ultrasound measurements of arterial IMT, whereas superficial femoral and popliteal arteries might be chosen for these studies besides carotid artery.
Rescue of Prothrombin-deficiency by Transgene Expression in Mice
Authors: Sun William , Coleman Mallory , Witte David , Degen Sandra
Published: March 2018

Prothrombin has diverse biological functions in addition to its well established role in blood coagulation. In order to study these functions in more detail mouse model systems are needed. Since deficiency of prothrombin in mice results in partial embryonic lethality and neonatal death, alternative approaches are required to study the biology of prothrombin in the adult mouse. The liver is the major site of synthesis of prothrombin and therefore liver-specific promoters were used to express prothrombin in transgenic mice. Mice generated from crosses with these transgenic mice and mice hemizygous for the knock-out allele were used to test whether liver-specific expression is sufficient to correct the phenotype of null mice and whether liver-specific expression is sufficient for the development and survival of mice to adulthood. The mouse albumin promoter/enhancer was used initially for transgene expression without success in obtaining transgene positive, endogenous prothrombin null mice. Two lines of transgene positive, endogenous prothrombin deficient mice were obtained using the mouse transthyretin (TTR) promoter/enhancer driving expression of a human prothrombin cDNA. One line was able to rescue both the embryonic and the neonatal lethality while the other line was only able to correct the embryonic lethality. Expression of prothrombin was restricted to the liver and stomach in one line and to the liver, pancreas, stomach and kidney in the other line of mice. Thrombin activity for one line was determined to be at 5-10% of wildtype levels. These mice developed normally and did not have spontaneous bleeding events unless traumatized. Therefore, transgenic expression of human prothrombin is sufficient for the rescue of the lethality found for prothrombin deficiency in mice.
A Fully Recombinant Partial Prothrombin Complex Effectively Bypasses fVIII
In Vitro
and
In Vivo
Authors: Himmelspach Michèle , Richter Günter , Muhr Evelyn , Varadi Katalin , Turecek Peter , Dorner Friedrich , Schlokat Uwe , Schwarz Hans
Published: March 2018

The development of inhibitory antibodies is a serious complication in hemophilic patients, severely compromising therapeutic success. Bleeding episodes in affected patients are controlled by treatment with a plasma-derived prothrombin complex concentrate (PCC), activated PCC (APCC) or recombinant activated factor VII. We hypothesized that a recombinant two-component agent consisting of recombinant prothrombin (rfII) and activated factor X (rfXa) would have substantial fVIII bypassing activity and could be a safe alternative therapeutic option. To test this hypothesis we assembled an agent in vitro solely consisting of rfII and rfXa at a molar ratio of 37,500:1. These factors are believed to be responsible for the activity of APCC preparations. Recombinant fX, used as the source for fXa generation, and rfII were purified from serum-free and protein-free conditioned media of stably transfected CHO and BHK tissue culture cells, respectively. Activation of rfX to rfXa was accomplished by the plant protease ficin, obviating the need for a protease derived from a human or animal source. We found that in vitro the complex reduced the abnormally prolonged activated partial thromboplastin time (APTT) of a high-titer fVIII inhibitor plasma similar to an APCC preparation. Furthermore, addition of increasing amounts of rfII/rfXa to inhibitor plasma resulted in a linear dose-dependent increase in the rate of thrombin generation. In a rabbit fVIII inhibitor model, treatment with rfII/rfXa statistically significantly reduced the intensity of the abnormal cuticle bleeding. In the Wessler test, rfII/rfXa showed no thrombogenicity. These data show that a well-defined, particularly safe and efficacious agent with fVIII bypassing activity can be generated from recombinant fII and fXa.
Combined Effects of Eptifibatide and Anticoagulants: Differences between LMWH and UH or rH in Thrombin Generation Inhibition but not in Platelet Aggregation Inhibition
Authors: Gallistl Siegfried , Cvirn Gerhard , Roschitz Birgit , Petritsch Martina , Leschnik Bettina , Muntean Wolfgang , Koestenberger Martin
Published: March 2018

Aim of our study was to investigate effects of eptifibatide and anticoagulants on platelet aggregation and thrombin generation under low and high coagulant challenge in tissue factor-activated platelet rich plasma using a model allowing simultaneous determination of the time course of platelet aggregation and thrombin generation. Eptifibatide exerted a dose-dependent anti-aggregating effect under both high and significantly stronger under low coagulant challenge. Combination of eptifibatide and anticoagulants resulted in significant additive prolongation of the lag phase until the onset of platelet aggregation, more pronounced under low coagulant challenge. Under high, but not under low coagulant challenge combination of eptifibatide and anticoagulants had a significant synergistic inhibitory effect on platelet aggregation. Under low coagulant challenge combination of eptifibatide with LMWH, but not with UH, or rH, resulted in significantly reduced thrombin potential, F 1+2 generation, and FXa formation compared to measurements in the absence of eptifibatide.

We demonstrate a synergistic effect of eptifibatide and anticoagulants on platelet aggregation inhibition and an additional inhibitory effect of LMWH and eptifibatide on thrombin generation. Our results support the notion that combination of eptifibatide and anticoagulants might be beneficial in atherosclerotic disease to palliate the thrombogenic potency of ruptured atherosclerotic plaques.
Molecular mechanisms of leukocyte recruitment: organ-specific mechanisms of action
Authors: Kubes Paul , Liu Lixin
Published: March 2018

Leukocyte recruitment in the microcirculation is a critical process underlying inflammatory responses in tissues. The mechanism of recruitment is summarized by the generally accepted paradigm: selectin-mediated leukocyte rolling, subsequent integrin activation, followed by integrin-mediated firm adhesion. This simple paradigm may not be able to explain the leukocyte recruitment mechanisms in some organs including the liver and brain. Recent studies suggested that these organs have their own leukocyte recruitment paradigms in acute and even chronic inflammation. The combination of unique hemo-dynamic patterns and specific structural and functional features of the vessels and endothelium in liver may dictate and select the specific patterns of leukocyte recruitment in this organ. In the brain microvasculature, where shears are high and adhesion molecule expression low, platelets may play an important role as a bridge between the leukocytes and endothelium.
A randomized trial of initial warfarin dosing based on simple clinical criteria
Authors: Patel Jeetendra , Kumar Juhi , Malik Aamir , Jaeger Joseph , Maida Mahamadu , Ord Linda , Burrows Grover , Shine Daniel
Published: March 2018

Warfarin induction is accomplished by titrating dosage to coagulation test results. Algorithms can guide this process but not identify the starting dose. We hypothesized that an initial warfarin dose approximating the maintenance value would safely enhance rapidity of induction. In a randomized trial we compared a fixed-dose to a maintenance-dose strategy for beginning warfarin therapy. To predict the maintenance dose among patients with differing warfarin requirements we performed regression analysis on clinical factors derived from chart review. Four community hospitals supplied records for retrospective analysis. The prospective trial was conducted in one, a 350-bed teaching institution. A sample of inpatients anti-coagulated during 1998 formed the development set for retrospective study; a 1999 sample formed the validation set. A one-year trial recruited consecutive eligible inpatients initiated on warfarin. We randomly assigned patients to a first warfarin dose calculated using our regression formula or fixed at 5 mg. All patients’ subsequent doses were determined (as a percentage of initial) from coagulation testing. We compared days to anticoagulation, hospitalized hours, complications, and activity of factor II and protein C in a patient sample at intervals after induction. Weight, age, serum albumin, and presence of malignancy explained 25-30% of variance in maintenance dose. Ninety patients (44 calculated-dose and 46 standard-dose) evaluated in the clinical trial. Mean time to anticoagulation (among patients achieving anticoagulation) was 4.2 and 5.0 days, respectively (p = 0.007). We observed no significant differences in other endpoints. Individualized initial dosing may safely hasten war-farin induction.
Effect of clotting factors concentrates on lymphocyte and neutrophil function in vitro
Authors: Ghio Massimo , Contini Paola , Ottonello Luciano , Arduino Nicoletta , Gringeri Alessandro , Indiveri Francesco , Dallegri Franco , Puppo Francesco
Published: March 2018

Immunological abnormalities have been reported in haemophiliacs. Although infections with HIV, hepatitis and other viruses may contribute to these abnormalities, immune defects are detectable also in HIV seronegative haemophiliacs. It is likely that chronic exposure to extraneous proteins in clotting factor concentrates (CFCs) may play a role in immunomodulation, but the underlying mechanisms remain unclear. The results of the present paper show that: a) soluble HLA class I (sHLA-I), soluble Fas-ligand (sFas-L) and transforming growth factor beta 1 (TGF-β1) are detectable in plasma derived but not in recombinant CFCs; b) the level of sHLA-I and sFas-L is proportional to the grade of CFCs purity whereas TGF-β1 showed very variable levels; c) soluble molecules detected in CFCs exert immunomodulatory effects in vitro like apoptosis induction in Jurkat cells and inhibition of mixed lymphocyte reaction response, antigen-specific lymphocyte cytotoxic activity and neutrophil chemotaxis.
Magnetic resonance direct thrombus imaging: a novel technique for imaging venous thromboemboli
Authors: Hunt Beverley , Moody Alan , Kelly James
Published: March 2018

Invasive testing is now seldom required in patients with suspected venous thromboembolism (VTE). However, a corollary of noninvasive imaging is increased complexity as results are often yielded as probabilities rather than definitive answers and additional testing is frequently required following initial imaging. This creates a milieu in which misunderstandings and protocol violations are common, potentially leading to diagnostic errors. A highly accurate noninvasive imaging technique which allows immediate treatment decisions to be made is needed. Magnetic resonance direct thrombus imaging (MRDTI) is a novel technique which detects methaemoglobin in clot, allowing visualisation of thrombus without using intravenous contrast. It has two major advantages over conventional modalities which identify it as having the potential to fill this role. Firstly, direct visualisation of thrombus overcomes many of the pitfalls of conventional techniques, which have either identified thrombus as a filling defect or in terms of surrogates. Secondly, simultaneous imaging of the legs and chest allows a comprehensive assessment of thrombus load, minimising the importance of overlooked subsegmental pulmonary embolism (PE) and potentially facilitating more titrated treatment.

Early data suggest MRDTI is highly accurate for the detection of both deep vein thrombosis (DVT) and PE, and ongoing outcome studies are evaluating the safety of withholding treatment in suspected DVT and PE on the basis of negative MRDTI alone. If favorable, a multi-centre outcome study evaluating cost-effectiveness as well as safety would be justified. Subject to further evaluation, this technique has the potential greatly to simplify and standardise the investigation of suspected VTE.
Prevalence of clopidogrel non-responders among patients with stable angina pectoris scheduled for elective coronary stent placement
Authors: Müller Iris , Besta Felicitas , Schulz Christian , Massberg Steffen , Schönig Albert , Gawaz Meinrad
Published: March 2018

Dual antiplatelet therapy with aspirin and clopidogrel decreases the rate of stent thrombosis in patients undergoing percutaneous coronary intervention (PCI). However, despite intensified antiplatelet treatment, up to 4.7% of the patients undergoing coronary stenting develop thrombotic stent occlusion, suggesting incomplete platelet inhibition due to clopidogrel resistance. We evaluated the percentage of clopidogrel nonresponders among 105 patients with coronary artery disease (CAD) undergoing elective PCI. All patients were treated regularly with aspirin 100 mg/d and received a loading dose of 600 mg clopidogrel followed by a maintenance dose of 75 mg/d before PCI. Clopidogrel non-responders were defined by an inhibition of ADP (5 and 20 μMol/L) induced platelet aggregation that was less than 10% when compared to baseline values 4 h after clopidogrel intake. Semi-responders were identified by an inhibition of 10 to 29%. Patients with an inhibition over 30% were regarded as responders. We found that 5 (ADP 5 μMol/L) to 11% (ADP 20 μMol/L) of the patients were non-responders and 9 to 26% were semi-responders. Among the group of nonresponders there were two incidents of subacute stent thrombosis after PCI. We conclude that a subgroup of patients undergoing PCI does not adequately respond to clopidogrel, which may correspond to the occurrence of thromboischemic complications. Point-of-care testing may help to identify these patients who may then benefit from an alternative antiplatelet therapy.
Anticoagulant serine fibrinogenases from Vipera lebetinavenom: structure-function relationships
Authors: Aaspõllu Anu , Siigur Jüri , Siigur Ene
Published: March 2018

Amino acid sequences of two anticoagulant serine fibrinogenases – α- and β-fibrinogenase (VLAF and VLBF) from Vipera lebetina venom have been deduced from the cDNA sequences encoding the enzymes. The mature protein sequences of 234 amino acids (VLAF) and 233 amino acids (VLBF) exhibit significant similarity with other snake venom serine proteinases. Both enzymes contain the catalytic triad His57, Asp102, Ser195, and twelve conserved cysteines forming six disulfide bridges. Unlike typical trypsin-like serine proteinases, they lack the third aspartate, Asp189 which is replaced by Gly189. VLBF is a typical representative of arginine esterases – β-fibrinogenases. α-Fibrinogenase, VLAF, is unique among snake venom serine proteinases with homologous structure. Until now there is no evidence of the anticoagulant serine enzymes degrading fibrinogen α-chain only and lacking esterolytic activity.

Parts of this paper were presented at the 17th International Fibrinogen Workshop of the International Fibrinogen Research Society (IFRS) held in Munich, Germany, September, 2002.

The sequence data of Vipera lebetina mRNA for α- and β-fibrinogenase have been deposited in the GenBank database under accession numbers AF528193 (VLAF) and AF536235 (VLBF).
Clopidogrel and warfarin: absence of interaction in patients receiving long-term anticoagulant therapy for non-valvular atrial fibrillation
Authors: Lidell Christer , Svedberg Lars-Erik , Lindell Peter , Bandh Stellan , Job Bernhard , Wallentin Lars
Published: March 2018

The effect of concomitantly administered clopidogrel on anticoagulation status was investigated in patients receiving long-term warfarin therapy. Forty-three patients with non-valvular atrial fibrillation who were receiving long-term warfarin and had a stable international normalized ratio (INR) between 2 and 3 were randomly assigned to clopidogrel 75 mg daily or placebo for 8 days (Days 1–8). INR (primary endpoint) and plasma levels of warfarin enantiomers (secondary endpoint) were evaluated at Days 3, 6, 9, 13 and 22. Mean INR remained extremely stable in the clopidogrel group, the maximum percentage change from baseline being 0.6% at Day 6. Plasma levels of R- and S-warfarin also remained very stable in those receiving clopidogrel. No serious adverse events, premature discontinuations of study drug or bleeding occurred with clopidogrel. In conclusion, the stable anticoagulation status of patients receiving long-term warfarin therapy is unaffected by concomitant administration of clopidogrel 75 mg daily.
Preoperative plasma fibrinogen levels predict mortality after coronary artery bypass grafting
Authors: Robinson Daniel , Kleine Volker , Hertwig Sabine , Schwahn Christian , Grimm Rita , Eckel Lothar , Rettig Rainer , Völzke Henry
Published: March 2018

This study was designed to investigate whether plasma fibrinogen levels as well as the β-fibrinogen –455 G/A genotype are associated with outcome after coronary artery bypass graft (CABG) operation.

We enrolled 249 consecutive CAD patients one day before they underwent a CABG operation. Data from 220 patients with available plasma fibrinogen levels were analyzed. The primary end-point was total mortality, the secondary end-point mortality from cardiac causes or the need for myocardial revascularization. The 2-year total mortality was 9.1% in the entire cohort. Multivariable analysis revealed an independent relationship between the primary end-point and preoperative plasma fibrinogen levels but not the β-fibrinogen –455 G/A geno-type. Neither preoperative plasma fibrinogen levels nor the β-fibrinogen –455 G/A genotype could predict the secondary end-point.

We conclude, that elevated preoperative plasma fibrinogen levels, but not the β-fibrinogen -455 G/A genotype predict the total mortality after CABG operation.
Tissue kallikreins: new players in normal and abnormal cell growth?
Authors: Yousef George , Diamandis Eleftherios
Published: March 2018

Serine proteases are proteolytic enzymes with an active serine residue in their catalytic site. Kallikreins are a subgroup of the serine protease family and are known to have diverse physiological functions. The human tissue kallikrein gene family has now been fully characterized and includes 15 members, clustered in a 300 kb region on chromosome 19q13.4. In this review, we discuss the common structural features of kallik-reins at the DNA, mRNA and protein levels. Kallikreins are secreted as inactive zymogens and are activated by cleavage of an N-terminal peptide. Some kallikreins can undergo autoactivation while others may be activated by other kallikreins or other proteases. Most kallikreins are predicted to have trypsin-like enzymatic activity except for three members which may have chymotrypsin-like activity. Circumstantial evidence suggests that at least some kallikreins may be part of an enzymatic cascade pathway which is activated in aggressive forms of ovarian and probably other cancers. Accumulating evidence suggests potential diagnostic and/or prognostic roles of kallikreins in diverse malignancies. In addition to PSA, many other kallik-reins show differential expression in malignancy. For example, hK6, 10 and 11 are promising serological markers for ovarian cancer diagnosis. KLK10 may act as a tumor suppressor. In addition to their diagnostic and prognostic values, kallikreins may also be good therapeutic targets.

Part of this paper was originally presented at the joint meetings of the 16th International Congress of the International Society of Fibrinolysis and Proteolysis (ISFP) and the 17th International Fibrinogen Workshop of the International Fibrinogen Research Society (IFRS) held in Munich, Germany, September, 2002.
Risk of venous thromboembolism in relatives of symptomatic probands with thrombophilia: a systematic review
Authors: Langlois Nicole , Wells Philip
Published: March 2018

Clinical equipoise exists regarding whether relatives of individuals with venous thromboembolism (VTE) and thrombophilia should be screened for thrombophilia. There have been no systematic attempts to summarize studies that have assessed the incidence of VTE in relatives. The purpose of this review was to systematically identify and review observational studies with thrombophilic relatives and to summarize their findings with respect to their risk of VTE.

We conducted a systematic literature review and included nine observational studies meeting a priori inclusion criteria. Potentially eligible studies evaluated VTE incidence in relatives of index patients (probands) with symptomatic thrombophilia. In the four prospective studies, the incidence of VTE for asymptomatic family members with factor V Leiden ranged from 0.58-0.67% per year, 1.0-2.5% for protein C deficiency, 0.7-2.2% for protein S deficiency, and 4% for antithrombin deficiency. About half of all VTEs occurred during well-known risk periods but incidence rates were decreased by use of prophylaxis. No deaths from pulmonary embolism or fatal hemorrhages from anticoagulants were reported. The incidence of VTE was generally lower in the retrospective studies. The pooled relative risk from four retrospective studies for factor V Leiden carriers was 3.69 (CI 2.27, 6.00) and from two studies the pooled relative risk for deficiencies of protein C, protein S, and antithrombin was 10.58 (CI 5.38, 20.81).

In conclusion, the risk of VTE events in asymptomatic relatives is low, but this may be an underestimate. Anticoagulant prophylaxis during risk periods appears to be of benefit but further research in this area is required.
Immunohistochemical localization of tissue factor pathway inhibitor-2 in human tumor tissue
Authors: Sierko Ewa , Zimnoch Lech , Kozlowski Leszek , Kisiel Walter , Wojtukiewicz Marek
Published: March 2018

The progression of neoplasms is frequently associated with thromboembolic complications. Coagulation proteins, particularly tissue factor (TF), have been shown to play a role in tumor growth and metastatic dissemination. TFPI is the principal inhibitor of TF-dependent pathway of blood coagulation, but previous studies failed to detect antigenic TFPI in cancer tissue. Recently, a second inhibitor of tissue factor dependent pathway, TFPI-2 (also known as placental protein 5 [PP5] or matrix-associated serine protease inhibitor [MSPI]), has been described. Information on the presence of TFPI-2 within the malignant tumor tissue still remains obscure, and thus the aim of this study was to evaluate the expression of TFPI-2 in loco in several different neoplasms. TFPI-2 expression was demonstrated by immu-nohistochemical procedures in neoplastic cells of laryngeal, breast, gastric, colon, pancreatic, renal and endometrial cancer, as well as glial neoplasms. The intensity of staining was not uniform, with higher intensity in more differentiated tumors. G3 breast, gastric, endometrial and colon cancer cells revealed populations of cells that were either TFPI-2 positive or negative. Gastric and renal cancer tissue exhibited the presence of TFPI-2 in tumor infiltrating macrophages. TFPI-2 was also observed in normal tissue of the breast, stomach, colon and pancreas. These data demonstrate that the expression of TFPI-2 diminishes with an increasing degree of malignancy, which may suggest a role for TFPI-2 in the maintenance of tumor stability and inhibition of the growth of neoplasms.
Mutations in the R2 FV Gene Affect the Ratio between the Two FV Isoforms in Plasma
Authors: Castoldi Elisabetta , Rosing Jan , Girelli Domenico , Hoekema Lico , Lunghi Barbara , Mingozzi Federico , Ferraresi Paolo , Friso Simonetta , Corrocher Roberto , Tans Guido , Bernardi Francesco
Published: March 2018

Molecular genetics and biochemical studies were performed in homozygotes for the R2 allele (4070G) in the factor V gene, most of them affected by coronary artery disease. Novel polymorphisms (G642T, 156Ser; T1328C, 385Met/Thr), among which a functional candidate (A6755G, 2194Asp/Gly) located in the C2 domain of FV, were identified in the R2 gene. In chromatographic studies R2 FV appeared qualitatively identical to normal FV. However, a relative increase of the more thrombogenic and more glycosylated FV isoform (FV1) was observed in plasma of 2194Gly homozygotes (mean FV1/FV2 ratio 0.71, 95% CI 0.66-0.77) as compared to R2-free controls (0.37, 95% CI 0.34-0.40). We conclude that carriership of the R2 FV gene is associated with an imbalance between the two functionally different FV isoforms, and propose that genetically determined differential glycosylation of FV could represent a novel mechanism of thrombotic disease.
Value of Chest X-ray Combined with Perfusion Scan versus Ventilation/Perfusion Scan in Acute Pulmonary Embolism
Authors: Turkstra Franktien , van Marwijk Kooy Marinus , Oostdijk Ad H. , van Beek Edwin J. , Büller Harry , de Groot Marco
Published: March 2018

BackgroundThe main purpose of ventilation scanning, as adjunct to perfusion lung scintigraphy, in acute pulmonary embolism is to allow for the classification of segmental perfusion defects as mismatched, which is generally accepted as proof for the presence of pulmonary embolism. We examined whether this function of the ventilation scan could be replaced by the chest X-ray.MethodsIn 389 consecutive patients with suspected pulmonary embolism and at least one segmental perfusion defect we classified the ventilation/perfusion (V/Q) scan and chest X-ray/perfusion (X/Q) scan as either mismatched or matched. Furthermore we analyzed whether this comparison was different in subgroups of patients with concomitant congestive heart failure or chronic obstructive pulmonary disease.Results Overall agreement between the X/Q and V/Q scan diagnostic category was found in 341 of 389 patients (88%; 95% CI 84-92%). The positive predictive value for obtaining a mismatched V/Q scan result in case of a mismatched X/Q scan result was 86% (95% CI 81-90%). If the X/Q scan yielded only matched defects the V/Q scan resulted in the same classification in 90% (95% CI 85-95%). Analysis of the small subgroup of patients with chronic obstructive pulmonary disease showed that a mismatched X/Q scan was confirmed by V/Q scanning in 21 of 34 cases (62%; 95% CI 45-78%).ConclusionThis study shows that in the great majority of patients with clinically suspected acute pulmonary embolism combination of chest X-ray with perfusion scintigraphy reliably replaced ventilation/perfusion scintigraphy in defining (mis)-matching of segmental perfusion defects. These results need confirmation before the chest X-ray can fully obviate the use of ventilation scintigraphy.
Haemostatic Factors in Human Peripheral Afferent Lymph
Authors: Howarth David , Attfield Janet , Cooke C. , Nanjee M. , Olszewski Waldemar , Morrissey James , Miller Norman , Miller George
Published: March 2018

Peripheral afferent lymph was obtained by cannulation of a collecting vessel in 17 healthy men (mean age 26 years). Lymph/plasma ratios of all vitamin K-dependent factors were lower than expected from molecular weight. Factor VII, factor IX and tissue factor pathway inhibitor (TFPI) lymph/plasma activity ratios were higher than antigen ratios. Activated factor VII (FVIIa) and TFPI-Xa complex concentrations were higher in lymph than plasma, and the raised FVIIa did not appear to be due to cannulation. The fibrinogen lymph/plasma activity (Clauss) ratio averaged about 20% of the antigen ratio. The result of an ELISA for D-dimer was higher in lymph than plasma, often more than five-fold. This high level in lymph was not explored but may indicate proteolysis of fibrinogen and fibrin with release of D-like and D-dimerlike fragments in interstitial fluid.
Cloning of Guinea Pig Tissue Factor cDNA: Comparison of Primary Structure among Six Mammalian Species
Authors: Shi Rui-Jin , Li Wen-Zhou , Marder Victor , Sporn Lee
Published: March 2018

Tissue factor (TF) is a transmembrane glycoprotein that serves as an essential cofactor for plasma coagulation factor VII. TF procoagulant activity exhibits varying species specificity. In particular, guinea pig (GP) TF is unable to activate clotting in heterologous plasma systems, but the molecular basis for this phenomenon is not yet understood. The full-length GP TF cDNA was cloned and sequenced. The open reading frame encoded a predicted precursor protein of 289 amino acids (aa) which was expressed in a reticulocyte lysate system as a protein of apparent molecular weight of 34 kD. The identity of the predicted aa sequence of mature GP TF with rabbit, human, bovine, rat and mouse TF was 66.4, 64.4, 60.6, 53.2 and 52.2%, respectively. With a focus on sites of potential functional significance, we compared sequences within the known binding regions. The eleven residues at the interface region between the TF1 and TF2 modules, which bind to the EGF domain of VIIa, were perfectly conserved among the six species, with the exception of an isoleucine replacing a lysine in the guinea pig sequence. However, only four of the eleven binding residues in the TF1 module, known to interact with the catalytic domain of factor VII, and three of the five residues in the TF2 module, involved in binding the factor VII Gla domain, were conserved among species. We hypothesize that divergence at these regions contributes to the specificity and non-reciprocity of TF procoagulant activity between species.
Use of Recombinant Factor VIIa in 3 Patients with Inherited Type I Glanzmann’s Thrombasthenia Undergoing Invasive Procedures
Authors: Ménart C. , Trzeciak M. C. , Nurden P. , Fressinaud E. , Dreyfus M. , Laurian Y. , Négrier C. , d’Oiron R.
Published: March 2018

The treatment of bleeds in Glanzmann’s thrombasthenia is a challenging issue, especially when repeated platelet transfusions have induced anti-glycoprotein (GP) IIb-IIIa or anti-HLA allo-immunisation. In an attempt to find an alternative treatment regimen, we used recombinant factor VIIa (rFVIIa, NovoSeven®, Novo Nordisk, Denmark) as first-line therapy in 3 patients with Glanzmann’s thrombasthenia and anti-GPIIb-IIIa iso-antibodies who were scheduled for invasive procedures. The administration of an initial bolus dose of rFVIIa (70–110 µg/kg) was immediately followed by continuous infusion at the rate of 9-30 µg/kg/h for 3–15 days. The treatment resulted in an excellent clinical efficacy and tolerance in 2 cases. In the third patient, whereas efficacy was excellent at the surgical site, pharyngonasal bleeds of traumatic origin persisted for 10 days, and a severe thromboembolic complication occurred 5 days after discontinuation of rFVIIa. Complementary studies are needed for patients with congenital platelet disorders in order to evaluate the safety and the potential therapeutic place of rFVIIa treatment.
Hemostatic Changes following the Modified Fontan Operation (Total Cavopulmonary Connection)
Authors: Ries Martin , Hofbeck Michael , Buheitel Gernot , Singer Helmut , Klinge Jens , Rauch Ralf
Published: March 2018

Thromboembolism is a serious complication after Fontan operation, which may be caused by alterations of the coagulation system. We therefore investigated pro- and anticoagulant factors in 20 patients aged 4 to 21 years, 4 to 63 months following total cavopulmonary connection. Furthermore we compared markers of thrombin activation and fibrinolysis and in vitro clotting and clot-lysis to age-matched healthy subjects.

Compared to results of age-matched controls, the Fontan operated individuals had significant decreases in levels of protein C (0.88 U/ml in controls, 0.67 U/ml in patients; p <0.001) and protein S (1.05 in controls, 0.93 U/ml in patients; p <0.05). Moreover, half of the patients had high values of FVIII (>1.5 IU/ml), which are associated with an increased thrombotic risk. These changes may result in enhanced generation of thrombin and plasmin, indicated by our finding of increased thrombin-antithrombin III (TAT) and plasmin-antiplasmin (PAP) levels and a similar trend in prothrombin fragments F1+2. Clot lysis tests, global coagulation tests, red blood cell count, liver enzymes AST, ALT, but not GGT, were generally within the normal ranges.
Involvement of Activated Integrin α2β1 in the Firm Adhesion of Platelets onto a Surface of Immobilized Collagen under Flow Conditions
Authors: Onitsuka Ichiro , Imaizumi Tsutomu , Jung Stephanie , Moroi Masaaki
Published: March 2018

Recently, we demonstrated that agonist-induced activation of the platelet surface collagen-receptor integrin α1 β2 converts it to an active form that can bind soluble collagen with high affinity (Jung, SM, Moroi, M: J Biol Chem 1998; 273: 14827-37). Here, the involvement of α2 β1 activation and the high affinity binding property of activated α2β1 in platelet adhesion to a collagen surface under flow conditions were analyzed. Platelet adhesion to immobilized collagen was measured in the presence of TS2/16, an activating anti-integrin α2β1 antibody, and inhibiting antibodies, Gi9 and 6F1. TS2/16 decreased the moving velocity of platelets on the collagen surface, but Gi9 and 6F1 increased it, indicating that α2β1 activation induces the tight binding of platelets to immobilized collagen under flow. Platelet adhesion, expressed as the surface area occupied by adhered platelets, in the presence of TS2/16 was similar to that in its absence. In contrast, adding Gi9 or 6F1 caused biphasic adhesion composed of a first phase, a lag phase whose length differed in each experiment, and a second phase adhesion with a rate similar to that of the control. This biphasic adhesion indicates that α2β1 activity is inhibited and also suggests that some other factor(s) may contribute to the adhesion under flow. At concentrations where neither 6F1 nor Gi9 affected collagen-induced aggregation, these antibodies inhibited soluble collagen binding to thrombin-activated platelets. Only at much higher concentration did 6F1 inhibit collagen-induced aggregation. TS2/16 had no effect on the aggregation. The present results are evidence against the major involvement of integrin α2β1 in platelet aggregation; instead, they indicate that integrin α2β1 would be mainly associated with the tight binding of platelets to collagen.
Quantification of Platelet-associated IgG for Differential Diagnosis of Patients with Thrombocytopenia
Authors: Schlenke P. , Hennig H. , Kirchner H. , Klüter H. , Hagenström H.
Published: March 2018

Immune thrombocytopenia is due to platelet destruction by circulating glycoprotein-specific antibodies and is found in various disorders. Methods for the detection of platelet-associated IgG (PAIgG) are generally sensitive but unspecific, whereas glycoprotein-specific assays are highly specific but less sensitive. Usefully, a sensitive screening method for PAIgG detection would also provide information for differential diagnosis. We developed a quantitative direct Platelet Immunofluorescence Test (PIFT) by flow cytometry and studied 79 thrombocytopenic patients with immune thrombocytopenia and other disorders. The sensitivity of the assay was 94%, its specificity 66% for the detection of a clinically obvious immune thrombocytopenia. PAIgG levels of patients with immune thrombocytopenia differed significantly from those of other patients with low platelet counts (p <0.001). The quantitative PIFT proved to be a sensitive method for PAIgG detection and should therefore be used as a screening method. In addition, it could be helpful for differential diagnosis in marked thrombocytopenia where a MAIPA is not feasible.