bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Plasma Levels of Factor Vile and Antigen Are More Strongly Associated with the 10 Base Pair Promoter (-323) Insertion than the Glutamine 353 Variant
Authors: Humphries Steve , Temple Anne , Lane Anne , Green Fiona , Cooper Jackie , Miller George 
Published: July 2018

SummaryIn a group of 705 healthy middle-aged men, we have examined the relationship between plasma levels of Factor VII (FVII) c and Factor VII antigen (FVIIag) and two polymorphisms in the FVII gene. One polymorphism alters arginine at position 353 to glutamine (R/Q), and the other is the result of a 10 base pair (bp) insertion in the promoter region at position -323 from the start of translation (0/1 Obp). The frequency for the Q allele was 0.105 (95% Cl 0.09-0.12) and for the lObp allele was 0.117 (95% Cl 0.10-0.13). Men who were carriers of either of the rare alleles had levels of FVIIc and FVIIag that were approximately 20% lower than non-carriers, and both of these effects were highly statistically significant (p < 0.0001). Strong allelic association was observed between the two polymorphisms, with R and 0 bp being on the same chromosome in 96% of cases, and Q and 10 bp being on the same chromosome in 90% of cases where this could be determined unambiguously (Delta = 0.92, X2 = 1206, p < 0.0001). This strong allelic association created three major genotype groups which were found to have significantly different levels of FVIIc (p < 0.001). In the 547 men homozygous for both common alleles (R/R & 0/0), mean (SD) FVIIc was 101 (29) as compared with 85 (30) in the 20 men with the genotype R/R & 0/10 and 81(23) in the 126 men with the genotype R/Q & 0/10, suggesting a larger lowering effect associated with the 10 bp allele (16%) compared to the Q allele (an additional 4%). The lowering effect on FVII associated with the 10 bp allele remained statistically significant after adjusting for the effect of the Q allele (p = 0.004 for FVIIc and p = 0.06 for FVIIag), but the effect associated with the Q allele was no longer significant after adjusting for the 10 bp allele, suggesting that the strongest effect on levels of FVIIc was associated with the 0/10 bp genotype. In the sample overall, plasma FVIIc was associated positively with serum triglyceride concentration and the slope of this relationship was significantly greater in those with the genotype R/R compared to the other groups combined (0.12 versus 0.02, p = 0.008) with differences of similar size seen in the 0/0 compared to 0/10+10/10 groups. However, using the combined genotypes, the slope of this relationship in the R/R & 0/10 group was 0.38 and was significantly steeper (p = 0 .0 1 ) than in the other two groups who did not differ in this respect (slopes 0.11 and 0.08). This effect was seen on four subsequent annual examinations, and was also evident in the relationship between FVIIag and triglyceride concentration (p = 0.003 for difference between groups measured at baseline only). These data suggest that part of the previously described effects on FVIIc levels associated with the R/Q polymorphism may be explained by genetic variation in the promoter region of the FVII gene.
Experimental Haemorrhagic Effect of Two-Domain Non-Glycosylated Tissue Factor Pathway Inhibitor Compared to Low Molecular Weight Heparin
Authors: Holst Jan , Lindblad Bengt , Matthíasson Stefan E , Stjernquist Ulf , Ezban Mirella , Østergaard Per B , Hedner Ulla 
Published: July 2018

SummaryThe glycosylated multivalent three-domain Kunitz inhibitor TFPI is a natural inhibitor of tissue factor-FVIIa complex in the presence of FXa. TFPI has an experimental antithrombotic capacity indistinguishable from LMWH in a prophylactic dose, regardless of glycosylation and of the third domain. An inherited equilibrium between antithrombosis and haemorrhage exists. The aim of the study was to evaluate whether a two-domain non-glycosylated TFPI (117QTFPI1−161) has a bleeding potential in a rat gastric mucosa model. Groups; placebo, LMWH (tinzaparin) 60 and 250 anti-Xa IU/kg and 117QTFPIM61−161 1.0 and 10.0 mg/kg, given i.v. (bolus injection), randomised double dummy design.All actively treated groups significantly prolonged both the bleeding volume (493-984 Μl) and the bleeding time (10-20 min) compared to placebo (41 Μl, 2 min). It was not possible to distinguish a difference between the lower dose of LMWH and 117QTFPI1−161 in either parameter (p = 0.23-0.71). The two doses of 117QTFPI1−161 caused elevation of plasma-TFPI, 18 and 150 times baseline value. Both LMWH doses (0.6-3.2 anti-Xa IU/ml) and both 117QTFPI1−161 doses (0.2-2.7 anti-Xa IU/ml), caused significant effect in the anti-Xa assay, however 117QTFPI1−161 significantly less. Only the largest dose of 117QTFPI1−161 caused significant prolongation in the APTT assay (34 s). Both doses of LMWH caused significant prolongation (60-300 s). LMWH was the only substance to prolong the dilute-PT assay.Non-glycosylated two-domain 1.0 mg/kg TFPI, yielding supra-physiological plasma concentration, has an experimental haemorrhagic potential indistinguishable from LMWH in a prophylactic dose. The effect mediated by this type of TFPI could primarily be due to an inhibition of FXa.
Prothrombin Time Sensitivity and Specificity to Mild Clotting Factor Deficiencies of the Extrinsic Pathway: Evaluation of Eight Commercial Thromboplastins
Authors: Massignon D , Moulsma M , Bondon P , Debize G , Abidi H , Buttin T , Bon C , Pillonchery G , Coeur P 
Published: July 2018

SummaryProthrombin-time (PT) sensitivity and specificity to mild clotting factor II, V, VII and X deficiencies have rarely been studied. We therefore carried out a prospective study, in 350 patients, of eight commercial thromboplastins (CTs) in their ability to detect mild clotting factor deficiencies, notably in factor VII. In each patient the factor II, V, VII and X clotting activities and PT performed with each CT were determined. For each CT, PT sensitivity and specificity in detecting factor deficiencies below 0.5 U/ml or below 0.4 U/ml were determined at various PTs, and then Receiver Operator Characteristic curves constructed. At optimum PT threshold level (sensitivity = specificity), exactitude varied from 0.64 to 0.74 (p < 0.01) and from 0.67 to 0.81 (p < 0.0001) in detecting deficiencies below 0.5 and 0.4 U/ml respectively. In conclusion, this study shows the limits of the PT test as performed with 8 CTs in patients with mild clotting factor deficiencies. The impact of such differences in sensitivity and specificity on monitoring certain patients subject to decrease in coagulation factor, and, in particular, of those under low-dose oral anticoagulant, remains to be determined.
Antiplatelet and Antithrombotic Effects of YM337, the Fab Fragment of a Humanized Anti-GPIIb/IIIa Monoclonal Antibody in Monkeys
Authors: Kaku Seiji , Kawasaki Tomihisa , Hisamichi Nami , Sakai Yumiko , Taniuchi Yuta , Inagaki Osamu , Yano Shinya , Suzuki Ken-ichi , Terazaki Chinami , Masuho Yasuhiko , Satoh Noboru , Takenaka Toichi , Yanagi Kennichi , Ohshima Norio 
Published: July 2018

SummaryThe antiplatelet and antithrombotic effects of the Fab fragment of the humanized antiplatelet glycoprotein (GP) IIb/IIIa monoclonal antibody C4G1 (YM337) were investigated in monkeys. First, the relationship between the inhibition of platelet aggregation and the prolongation of bleeding time was studied in rhesus monkeys. YM337 dose-dependently inhibited ex vivo platelet aggregation, with complete inhibition at doses higher than 0.25 mg/kg intravenous injection or 1.5 μg/kg/min infusion. At 0.25 mg/kg bolus injection followed by 1.5 μg/kg/min infusion, YM337 immediately and continuously inhibited platelet aggregation during the 6-h infusion period with platelet aggregation rapidly returning to over 50% of baseline within 1 h after the cessation of infusion. Template-bleeding time was significantly prolonged during the period of complete inhibition of platelet aggregation.Second, the antithrombotic effects of YM337 were investigated in a photochemically-induced thrombosis model in squirrel monkeys. YM337 at a dose of 1 mg/kg intravenous injection followed by 6 μg/kg/min infusion for 60 min prevented occlusive thrombus formation in all 4 monkeys. In contrast, time to occlusive thrombus formation did not change on intravenous bolus injection of aspirin 17 mg/kg (11.3 ± 5.2 min) or sodium ozagrel (9.4 ± 3.0 min) compared with saline (13.3 ± 4.0 min). YM337 but not aspirin or sodium ozagrel significantly inhibited ex vivo ADP-induced platelet aggregation, while all drugs completely inhibited arachidonic acid-induced platelet aggregation. However, while aspirin and sodium ozagrel inhibited the thromboxane B2 generation accompanying arachidonic acid-induced platelet aggregation, YM337 had no effect on this variable. Platelet counts and bleeding time showed no significant change in any group in this squirrel monkey model.These results indicate that YM337, with a short half-life, may be a useful therapeutic agent in patients with thrombotic disorders.
Collagen Induced Thrombus Formation at the Apex of Eccentric Stenoses - A Time Course Study with Non-Anticoagulated Human Blood
Authors: Barstad R Marius , Kierulf Peter , Sakariassen Kjell S 
Published: July 2018

SummaryAtherosclerotic plaque rupture may trigger the formation of a mural thrombus. This thrombus formation is apparently affected by very high and complex shear conditions introduced by the luminal narrowing (stenosis) of the atheroma. To study the impact of such blood flow behaviour on thrombus formation we employed a model system where collagen-induced thrombogenesis is studied at the apex of well-defined eccentric stenoses.Thrombus formation in non-anticoagulated human blood drawn directly from an antecubital vein over the collagen coated stenosis apex for periods of 0.5, 1, 3 or 5 min was quantified by morphometry. The stenoses reduced the cross-sectional area of the blood flow channel by 60, 80 and 89%, which corresponded to apex wall shear rates of 2600, 10,500 and 32,000 s−1, respectively. Platelet-collagen adhesion decreased by increasing shear at the stenosis apex. The corresponding adhesion rates were highest at 1 min, then they gradually decreased upon prolongation of the perfusion time. The platelet thrombus volume increased in concert with increasing shear rate up to 10,500 s−1, whereas, at 32,000 s−1, the volume was decreased. The corresponding growth rates and rates of thrombus occlusion at the apex levelled off at 3 min. Significant fibrin deposition was not observed before 3 min, and was most pronounced at 10,500 and 32,000 s−1. The plasma levels of fibrinopeptide A and P-thromboglobulin increased in concert with increasing shear and perfusion time, particularly at the two highest shear conditions.Thus, hallmarks of thrombus formation at these stenoses with increasing shear are decreased platelet-collagen adhesion, and increased platelet-platelet interaction and fibrin deposition. A fibrin tail downstream to the collagen-attached platelet thrombus is regularly observed when thrombus occlusion exceeds 40%. However, the reduced thrombus growth at the most occlusive stenosis (89%) is presumably due to the high shear stresses which may reduce the rate of platelet incorporation into the thrombus and/or tear off thrombus fragments.
Heightened Thrombin Generation in Individuals with Resistance to Activated Protein C
Authors: Martinelli Ida , Bottasso Bianca , Duca Francesca , Faioni Elena , Mannucci Pier Mannuccio 
Published: July 2018

SummaryWe chose to evaluate whether or not a state of biochemical hypercoagulability was present in 74 individuals (69 heterozygotes and 5 homozygotes) resistant to activated protein C (APC) due to the Arg506 -> Gin mutation in the factor V gene. To this end, plasma levels of two markers of thrombin formation, prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin complexes (TAT), were measured. High levels of F1+2 and TAT were found in 32% and 23% of APC-resistant individuals vs 4% in controls. The levels of these markers tended to be particularly elevated in three homozygous subjects. A significant positive correlation between F1+2 and TAT was present in APC-resistant individuals. No relationship between marker values and the previous occurrence of thrombotic episodes was found. Therefore, by measuring F1+2 and TAT a state of biochemical hypercoagulability has been identified in about one-third of APC-resistant individuals. This frequency is similar to that previously observed in comparable individuals with inherited deficiencies of protein C and protein S, which are usually associated with a stronger thrombotic tendency than APC-resistant individuals.
Reactivity to β2 Glycoprotein I Clearly Differentiates Anticardiolipin Antibodies from Antiphospholipid Syndrome and Syphilis
Authors: Forastiero R R , Martinuzzo M E , Kordich L C , Carreras L O 
Published: July 2018

SummaryAnticardiolipin antibodies (aCL) detected by standard ELISA are found in association with autoimmune and infectious diseases. It is now recognized that P2 glycoprotein I (β2GPI) is a cofactor for aCL binding to cardiolipin (CL). To examine differences in cofactor requirements, aCL positive sera from patients with the antiphospholipid syndrome (APS) and syphilis were studied. Using an ELISA with human purified P2GPI adsorbed onto irradiated plates, we detected high binding activity in 29 out of 35 samples from APS patients and low in only 1 out of 37 aCL positive syphilis sera. Moreover, a good correlation (r = 0.79) was also observed in the former group between aCL and anti β2GPI. Whole IgG and affinity purified IgG aCL from APS patients did not bind to CL in the absence of β2GPI, but recognized β2GPI on irradiated plates in the absence of phospholipids. In contrast, IgG purified from syphilis patients only bound to CL alone. Taken together, these data indicate that performing both ELISA (aCL and anti β2GPI) it could be possible to distinguish aCL from autoimmune or infectious diseases.
Autoantibodies to Phospholipid-binding Plasma Proteins in Patients with Thrombosis and Phospholipid-reactive Antibodies
Authors: Pengo V , Biasiolo A , Brocco T , Tonetto S , Ruffatti A 
Published: July 2018

SummaryAnti-phospholipid (aPL) antibodies are defined as antibodies detected in systems employing phospholipids (PL). This general definition is misleading as it comprises a large group of autoimmune phospholipid-reactive antibodies that are directed against specific phospholipid-binding plasma proteins, such as β2-glycoprotein I (β2GPI) and prothrombin. Definition of phospholipid-reacting antibodies according to the plasma protein against which they are directed appears more appropriate and could be useful in understanding clinical events and pathogenic mechanisms. Using ELISA systems we have studied the presence of antibodies directed against specific phospholipid-binding proteins in a series of 22 patients with thrombosis and phospholipid-reactive antibodies of the IgG isotype. High levels of anti-β2GPI IgG were detected in all 22 patients. Normal values were calculated on the basis of OD values at 405 nm (OD405) obtained for 22 age- and sex-matched healthy subjects (cut off value = 0.401). Levels of anti-β2GPI antibodies were linearly correlated with those of cardiolipin-reactive (aCL) antibodies. Eleven out of 22 patients (50%) had values of anti-prothrombin antibodies exceeding the cut-off value of 0.250. No relationship was found between the levels of anti-β2GPI and anti-prothrombin antibodies. Tests for antibodies against two natural inhibitors of blood coagulation, protein C and protein S, revealed elevated levels of anti-protein C IgG and anti-protein S IgG in 4 and 12 patients, respectively. A highly significant correlation between anti-protein C IgG and anti-protein S IgG values as well as between antibody titers against the two studied natural coagulation inhibitors and anti-prothrombin IgG was found. When comparing patients positive for aCL and presence or absence of a previous thrombotic episode (aCL+/T+ vs aCL+/T-), the positivity of anti-P2GPI IgG was found to be statistically associated with thrombosis. Conversely, among patients with previous thromboembolism with or without aCL (aCL+/T+ vs aCL-/T+) the positivity of anti-β2GPI IgG was strictly associated with the positivity of aCL, thus identifying the aPL antibody syndrome. These data demonstrate that anti-β2GPI antibodies are a marker of “autoimmune” thrombosis. Anti-prothrombin antibodies are not a marker of thrombosis and are closely associated with antibodies to protein C and protein S.
Simple and Rapid Detection of Factor V Leiden by Allele-specific PCR Amplification
Authors: Blasczyk Rainer , Ritter Markus , Thiede Christian , Wehling Jenny , Hintz Günter , Neubauer Andreas , Riess Hanno 
Published: July 2018

SummaryResistance to activated protein C is the most common hereditary cause for thrombosis and significantly linked to factor V Leiden. In this study, primers were designed to identify the factor V mutation by allele-specific PCR amplification. 126 patients with thromboembolic events were analysed using this technique, PCR-RFLP and direct sequencing. The concordance between these techniques was 100%. In 27 patients a heterozygous factor VGln506 mutation was detected, whereas one patient with recurrent thromboembolism was homozygous for the point mutation. Due to its time- and cost-saving features allele-specific amplification should be considered for screening of factor VGln506.
Increased Activation of the Haemostatic System in Men at High Risk of Fatal Coronary Heart Disease
Authors: Miller George J , Bauer Kenneth A , Barzegar Samad , Cooper Jacqueline A , Rosenberg Robert D 
Published: July 2018

SummaryThe haemostatic system was examined in 2951 men aged 50 to 61 years, clinically free of cardiovascular disease, who were ranked according to a risk score for fatal coronary heart disease (CHD). Risk was judged from their serum cholesterol concentration, systolic blood pressure, body mass index and smoking habit. The status of the factor VH-tissue factor pathway was estimated from the plasma levels of factor VII coagulant activity, factor VII antigen and activated factor VII. Activation of factor IX was assessed from the plasma concentration of factor IX activation peptide. Activity within the common pathway was measured as the plasma concentrations of prothrombin fragment 1+2 and fibrinopeptide A. All 6 markers of haemostatic status were positively and statistically significantly associated with risk, providing further evidence for a hypercoagulable state in men at high risk for fatal CHD. Plasma fibrinogen and serum triglyceride concentrations were also graded positively with risk.
Detection of Circulating Tissue Factor and Factor VII in a Normal Population
Authors: Albrecht Sybille , Kotzsch Matthias , Siegert Gabriele , Luther Thomas , Großmann Heinz , Großer Marianne , Müller Martin 
Published: July 2018

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.
Enhanced Platelet Aggregability under High Shear Stress after Treadmill Exercise in Patients with Effort Angina
Authors: Tokuue Junya , Hayashi Junichi , Hata Yoshiya , Nakahara Kazuhiko , Ikeda Yasuo 
Published: July 2018

SummaryPlatelet activation induced by shear forces occurring in a stenosed coronary artery is one of the mechanisms of coronary thrombosis. We evaluated the shear-induced platelet aggregation (SIPA) dynamics in patients with effort angina during treadmill exercise. SIPA was measured by a rotational cone-plate aggregometer. SIPA was markedly increased by exercise from 71.2 ± 8.9% to 81.9 ± 7.6% (p <0.01) in the patient group. Although epinephrine concentrations were elevated, its rate of increase was not correlated with that of SIPA. Yohimbine partially inhibited the exercise-induced increase in SIPA. In contrast, a significant correlation between the changing rate of plasma von Willebrand factor (vWF) larger multimers and that of SIPA (r = 0.74, p <0.05) was observed. Exercise-augmented SIPA is probably dependent on an increase in vWF larger multimers rather than platelet alpha2-receptor activation. Prevention of the interaction between vWF and its platelet receptors may play some role in decreasing the risk of coronary thrombosis during exercise.
Assessment of a Bleeding Risk Index in Two Cohorts of Patients Treated with Oral Anticoagulants
Authors: van der Meer F J M , Rosendaal F R , Vandenbroucke J P , Briët E 
Published: July 2018

SummaryIn two cohorts of patients on oral anticoagulant therapy, routinely treated by the Leiden Thrombosis Service, the frequency of major bleeding complications was assessed during two years (1988 and 1991). With Poisson regression analysis the influence of the risk factors age, sex, target zone, achieved INR and type of coumarin derivative used were determined. Subsequently, a bleeding risk index was calculated, combining the results of the two cohorts. For various types of patients the relative risk of major bleeding complications was assessed.Age and achieved INR were the most important and consistent risk factors: rate ratio (RR) for age in 1988 1.46 per 10 years increase (95% confidence interval [Cl] 1.20-1.78) and in 1991 1.57 per 10 years increase (95% Cl 1.23-2.00); RR per unit increase in achieved INR in 1988 1.42 (95% Cl 1.21-1.68) and in 1991 1.44 per unit increase in achieved INR (95% Cl 1.18-1.74). Two methods were used to combine the results of 1988 and 1991. In the first method the mean bleeding risk index was calculated: In (incidence) [natural logarithm of the incidence rate of major bleeding] = -5.64 +0.42 * age +0.26 % sex -0.29 * target range +0.36 % achieved INR -0.36 * coumarin type. In the second method only the consistent risk factors age and achieved INR were used: In (incidence) = -5.64 +0.42 % age +0.36 % achieved INR. These bleeding risk indexes can be used to assess the risk of major bleeding complications of individual patients and allow more individualized care by individual tailoring the desired anticoagulation.
Mutation in the Gene Coding for Coagulation Factor V and Resistance to Activated Protein C: Detection of the Genetic Mutation by Oligonucleotide Ligation Assay Using a Semi-automated System
Authors: Zotz Rainer B , Maruhn-Debowski Beate , Scharf Rüdiger E 
Published: July 2018

SummaryResistance of coagulation factor Va to inactivation by activated protein C (APCR) is associated with a point mutation in which adenine is substituted for guanine at nucleotide 1691 in the gene coding for factor V (FV Leiden). To date, this mutation of factor V is the most frequent genetic risk factor for venous thrombophilia. In this report, we describe the adaptation of an automatable oligonucleotide ligation assay (OLA) to detect the mutation in polymerase chain reaction-amplified DNA samples from 40 normal, 20 affected heterozygous, and 3 affected homozygous individuals. The genotypes determined by conventional allele-specific restriction enzyme site analysis were in complete concordance with the results obtained by ELISA-based oligonucleo-tide-ligation assay. The automated oligonucleotide ligation assay provides a rapid, reliable, nonisotopic method to detect the mutation responsible for APCR that can rapidly be applied to large population screening.