bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactivity of Soluble Fibrin Assays with Plasmic Degradation Products of Fibrin and in Patients Receiving Fibrinolytic Therapy
Authors: McCarron Bonnie , Marder Victor , Francis Charles 
Published: March 2018

SummaryThe ability to identify the products of thrombin and plasmin action on fibrinogen is important in patients with thrombotic and fibrinolytic disorders. New assays have been developed for “soluble fibrin” which represents soluble derivatives other than fibrinopeptides formed from fibrinogen by thrombin. These assays are either immunological, using antibodies for fibrin-specific neoepitopes, or functional and based on the cofactor activity of soluble fibrin in the tissue plasminogen activator (t-PA)-mediated conversion of plasminogen to plasmin. As plasmic derivations of fibrin share structural features with soluble fibrin, they may be reactive with assays for soluble fibrin. Therefore, we prepared plasmic digests of fibrin and determined the degree of reactivity with four soluble fibrin assays. Three assays used Mabs directed toward the fibrin-specific neoepitopes at α17-23 (A), γ312-324 (B) and α17-78 (D). A fourth (C) was based on t-PA co-factor activity. Tests A and C demonstrated marked crossreactivity with fibrin degradation products, and digests containing the largest derivatives showed greatest reactivity. Plasmic derivatives of crosslinked fibrin had greater reactivity than those of non-crosslinked fibrin. Tests B and D demonstrated minimal reactivity with plasmic derivatives of crosslinked or of non-crosslinked fibrin. Samples from patients with lower limb peripheral arterial occlusion were assayed for soluble fibrin, D-dimer and fibrinogen at presentation and eight hours after thrombolytic therapy. Variable results were seen at presentation with elevations in 13, 1, 0 and 4 of 19 patients using Tests A, B, C and D, respectively. After fibrinolytic therapy, marked increases in soluble fibrin levels were observed up to 600-fold above normal. A strong correlation between baseline levels was observed with Test B and Test D, which showed the least cross-reactivity with plasmic derivations. After thrombolytic therapy there were either weak or no correlations among the different assays. The results demonstrate that assays for soluble fibrin may react with plasmic derivatives of fibrin and this must be considered in interpreting clinical results.
Differential Regulation of Platelet Aggregation by Matrix Metalloproteinases-9 and -2
Authors: Fernandez-Patron Carlos , Martinez-Cuesta Maria , Salas Eduardo , Sawicki Grzegorz , Wozniak Mieczyslaw , Davidge Sandra , Radomski Marek 
Published: March 2018

SummaryWe have recently found matrix metalloproteinase-2 (MMP-2) in human platelets and reported that the release of this enzyme during platelet activation stimulates aggregation. We have now identified matrix metalloproteinase-9 (MMP-9) in human platelets and resistance-sized (~200 μm) arteries. Resting platelets released small quantities of pro-MMP-9. Maximal release of MMP-9 was detected during partial (appr. 30% maximum) aggregation with thrombin. However, maximal release of MMP-2 was associated with maximal aggregation. MMP-9 antibodies induced aggregation of resting platelets and potentiated aggregation of platelets induced by thrombin and collagen. Moreover, MMP-9 microisolated from arteries as well as recombinant human MMP-9 (0.1-30 ng/ml) inhibited thrombin and collagen-induced aggregation. We conclude that MMP-9 is an inhibitor of aggregation and in this action opposes the effects of MMP-2. The MMP-2/MMP-9 system may play an important role in the regulation of platelet-platelet and platelet-vessel wall interactions.
A Sudden Increase in Plasma Epinephrine Levels Transiently Enhances Platelet Deposition on Severely Damaged Arterial Wall
Authors: Martínez-González José , Royo Teresita , Lassila Riitta , Badimon José Juan , Badimon Lina 
Published: March 2018

SummaryEpidemiologic evidence has shown that sympathoadrenal activation plays a triggering role in the onset of acute coronary syndromes. However, its mechanism is not yet clearly understood. The aim of this study was to assess the effect of a sudden increase in epinephrine on platelet deposition on severely damaged vessel wall at shear rate conditions modelling stenotic vessels in the porcine model. The selected epinephrine concentrations (0.5 μmol/l-1 mmol/l) alone or in combination with collagen or ADP did not affect platelet aggregation in vitro either in whole blood or in PRP, although porcine platelets express α2-adrenergic receptors as assessed by PCR. In vitro and ex vivo perfusion experiments were performed using the Badimon chamber at high shear rate conditions (1690 s-1). In vitro, epinephrine (130 nmol/l) increased platelet deposition on severely damaged vessel wall (exposing tunica media; ≈1.6-fold, p <0.05) or immobilized collagen (2.2-fold, p <0.01). Ex vivo perfusion experiments were performed from animals that received intravenous epinephrine infusion for one hour at a low (0.3 μg/kg/min; ≈17 nmol/l in plasma, at 20 min of the infusion) and a high dose (1.0 μg/kg/min; ≈106 nmol/l in plasma, at 20 min of the infusion). Only the low dose temporarily increased platelet deposition on severely damaged vessel wall during the first 30 min of infusion [2.4-fold (p <0.05) and 4.2-fold (p <0.01) at 10 and 30 min of the infusion respectively] declining afterwards. Thus, in flow conditions typical of atherosclerotic arteries, a sudden physiological release of epinephrine can temporarily enhance platelet deposition on severely damaged vessel wall while an extensive exposure leads to refractoriness.
Rapid Haemodynamic Improvement Following Saruplase in Recent Massive Pulmonary Embolism
Authors: Barnes Sarah , Hopkins Gwyn , Charbonnier Bernard , Pacouret Gérard 
Published: March 2018

SummaryIn a single centre pilot study, saruplase (20 mg bolus plus 60 mg infusion over 1 h) was administered to twenty patients with an angio-graphically documented recent massive pulmonary embolism: Miller index of at least 20 and mean pulmonary artery pressure of at least 20 mmHg. The lytic ability of saruplase to cause normalization of haemodynamic parameters over the first 12 h and reperfusion of pulmonary arteries at 24 h was assessed. A decrease of 25 ± 10% in total pul monary resistance was evident at 30 min. Haemodynamic parameters continued to improve with total pulmonary resistance decreasing by 29 ± 8% and 40 ± 11% at 1 and 12 h respectively. Relative improve ment in Miller index 24 ± 6 h after saruplase treatment was 38 ± 9%. Two patients suffered recurrent pulmonary embolism, two severe bleeding events were observed. One patient died following a haemorrhagic stroke.
Pharmacodynamics and Tolerance of Two Nadroparin Formulations (10,250 and 20,500 Anti Xa IU·ml-1) Delivered for 10 Days at Therapeutic Dose
Authors: Navarro C. , Cambus J. P. , Caplain H. , d’Azemar P. , Necciari J. , Duret J. P. , Gaud C. , Sié P. , Boneu B. 
Published: March 2018

SummaryVenous thromboembolism may be efficiently treated by once-a-day (o.d.) administration of a high dose of low molecular weight heparin (LMWH) instead of administration of the same total dose in two injections a day (b.i. d.). To reduce the volume of the subcutaneous (s.c.) injection, a more concentrated form of the drug is advisable. This study was designed to compare the bioavailability of 2 formulations of nadroparin containing 10,250 and 20,500 anti-Xa IU·ml-1 respectively. This was an open, randomized, cross-over study where 12 healthy volunteers (age 18-35) were enrolled. They received either 90 anti-Xa IU·kg-1 b.i. d. of the 10,250 IU preparation (treatment A), or 180 anti-Xa IU·kg-1 o.d. of the 20,500 IU preparation (treatment B) for 10 days. On day 1, the subjects were sampled between 0 and 12 h (treatment A) or between 0 and 24 h (treatment B). On day 10, they were sampled between 0 and 12 h and between 12 and 24 h (treatment A) or between 0 and 24 h (treatment B). Anti-Xa and anti-IIa activities were determined by specific chromogenic assays. The main result of the study was that the bioavailability of the anti-Xa activity of the 2 nadroparin formulations was equivalent, as shown by the comparison of the AUC0-12 h plus AUC12-24 h (treatment A) and the AUC0-24 h (treatment B), calculated on day 10. This study also allowed a number of interesting observations to be made. 1) Between day 1 and day 10, there was an accumulation of the anti-Xa activity for treatment A but not for treatment B (accumulation factors: 1.6 and 1.1 respectively); 2) On day 10, the AUC0-12 h were slightly but significantly lower than the AUC12-24 h suggesting a circadian effect for anti-Xa and anti-IIa activities; 3) the clearance of the anti-Xa activity was comparable at the 2-dose regimens, while that of the anti-IIa activity was lower in treatment B than in treatment A, indicating a significant dose effect for the pharmacodynamics of the longer heparin chains; 4) On average, the clearance of the anti-IIa activity was twice as high as that of the anti-Xa activity; 5) For treatment B, significant APTT prolongations were noticed at Tmax (prolongation factor: 1.7 ± 0.25), in relation with the anti-IIa activity (0.3 ± 0.1 IU·ml–1).
4G/5G Promoter PAI-1 Gene Polymorphism Is Associated with Plasmatic PAI-1 Activity in Italians: A Model of Gene-Environment Interaction
Authors: Burzotta Francesco , Castelnuovo Augusto Di , Amore Concetta , D’Orazio Andria , Bitondo Rosa Di , Donati Maria Benedetta , Iacoviello Licia 
Published: March 2018

SummaryThe PAI-1 gene promoter 4G/5G polymorphism was found to be associated with plasma PAI-1 activity in Northern and Central Europe populations, but no data are available on the association between this polymorphism and PAI-1 levels in Southern Europe countries (such as Italy) where the incidence of ischemic disorders is lower. This study shows that among populations with different incidence of atherothrombotic disorders the 4G/5G PAI-1 gene promoter polymorphism has the same importance in the regulation of plasma PAI-1 activity.Moreover, we have analysed some gene-environmental interactions: the correlation between PAI-1 and cholesterol in non dyslipidemic subjects and the correlation between PAI-1 activity and tryglicerides in dyslipidemic subjects differed according to the 4G/5G genotype class. Thus, our findings suggest that, among subjects with or without metabolic disorders such as dyslipidemia, completely different gene-environment interactions may occur.
Thrombomodulin in Human Plasma Contributes to Inhibit Fibrinolysis through Acceleration of Thrombin-dependent Activation of Plasma Procarboxypeptidase B
Authors: Hosaka Yoshitaka , Takahashi Yasuo , Ishii Hidemi 
Published: March 2018

SummaryThrombomodulin (TM) expressed on endothelial cells binds thrombin and initiates anticoagulant pathways. Soluble functional proteolytic fragments of TM are also present in circulating plasma. Recently, it was reported that TM accelerated thrombin-dependent plasma procarboxypeptidase B (pro-pCPB) activation in a purified system and suggested that TM may inhibit fibrinolysis in crude plasma. The aim of present study was to evaluate any functional role of soluble TM fragments in plasma or purified TM added into plasma to the regulation of coagulation and fibrinolysis. Addition of rabbit TM (1-200 ng/ml) to plasma resulted in a concentration-dependent prolongation of urokinase (UK)- or tissue plasminogen activator (t-PA)-induced clot lysis time. The concentration of TM required for the inhibition of fibrinolysis was lower than that required for the inhibition of coagulation. Addition of anti-rabbit TM IgG or anti-human TM IgG into plasma reduced UK- or t-PA-induced clot lysis time without affecting clotting times, indicating that exogenous TM or soluble TM fragments in normal human plasma participated in regulation of fibrinolysis. Moreover, the TM-dependent inhibition of fibrinolysis was observed only in the presence of thrombin and blocked by addition of carboxypeptidase B inhibitors, but not mediated by protein C activation or direct inhibition of UK, t-PA or plasmin. Analysis of various substrates and inhibitors indicated that TM accelerated thrombin-dependent pro-pCPB activation in plasma. The present results indicate that TM, including soluble TM fragments in plasma, inhibit fibrinolysis via activation of pro-pCPB in plasma.
Anti-thrombotic Effects of CX-397, a Recombinant Hirudin Analog, in a Canine Model of Coronary Artery Thrombosis
Authors: Hori Toshimitsu , Moriike Mie , Asano Taiji , Hayashi Hideya , Iwade Kazunori , Hosoda Saichi , Ohyama Tadashi 
Published: March 2018

SummaryCX-397, a recombinant hirudin analog, is a potent and specific inhibitor of human α-thrombin. We conducted a comparative study of CX-397 and heparin in a canine model of left circumflex (LCX) coronary artery thrombosis to evaluate the anti-thrombotic efficacy of CX-397. Administration of drugs (i. v.; bolus + infusion) was commenced 10 min prior to the initiation of LCX coronary artery electrolytic injury (100 μA for 300 min). All saline-treated control animals (7/7) developed thrombotic occlusion during the experimental period, leaving a residual thrombus mass of 15.4 ± 3.8 mg. Treatment with CX-397 at three incremental dose levels reduced the incidence of occlusion (4/7, 2/5 and 0/7) and decreased thrombus weight (12.6 ± 2.5 mg, 6.3 ± 3.0 mg and 2.1 ± 1.3 mg, respectively) in a dose-dependent manner. At the in termediate dose (15,000 ATU/kg + 15,000 ATU/kg/h) or higher, CX-397 showed significant anti-thrombotic effects (p <0.05 and p <0.01) and suppressed increases in thrombin-antithrombin III complex (TAT) levels (p <0.01 and p <0.001). In the heparin (80 U/kg + 60 U/kg/h)-treated group, the incidence of occlusion (5/7) and thrombus weight (14.1 ± 6.2 mg) did not differ significantly from the control group. Plas ma TAT levels in the heparin group decreased compared with the control group (p <0.01), but was less potent than the intermediate dose CX-397 (p <0.01). The anti-coagulation (activated partial thromboplastin time and activated clotting time) and template bleeding time prolongation effects of heparin were more potent than those of the intermediate dose CX-397 which showed significant anti-thrombotic effects. In conclusion, CX-397 dose-dependently suppressed thrombus formation by inhibition of thrombin activity in a canine coronary artery injury model. The anti-thrombotic efficacy of CX-397 was more potent than that of heparin at equivalent anti-coagulation dosage.
Nucleotide Structure and Characterization of the Murine Gene Encoding Anticoagulant Protein C
Authors: Jalbert Louise , Rosen Elliot , Lissens Ann , Carmeliet Peter , Collen Désiré , Castellino Francis 
Published: March 2018

SummaryThe 15,160 bp murine gene encoding anticoagulation protein C (PC) was cloned and sequenced, including 414 bp upstream of exon 1 and 80 bp downstream of the translation stop codon. Nine exons and eight introns were identified. The first exon was untranslated and contained the major transcriptional start site, the surrounding nucleotide sequence of which matched reasonably well with the consensus eukaryotic Cap element sequence. The translational initiator methio-nine residue was located in exon 2. The other introns were positioned as splices between the major domain units of the protein. The 5’ untranslated region contained two possible CCAAT sequences and GC boxes, but no TATA box was obvious within the optimal range of distances from the transcription start site. The 3’-flanking nucleotides included a probable polyadenylation site (ATTAAA), beginning 80 nucleotides downstream of the translation stop codon, and a downstream consensus sequence (AGTGTTTC) required for the efficient formation of a 3’ terminus of mRNA. Several high probability transcription factor recognition sequences, including proteins that are enriched in, or specific to, the liver, such as C/EBP, C/EBP, HNF1, and HNF3, have been located in the 5’ region of the gene. These results indicate that all elements are present for liver-based transcription of the gene for murine PC.
A Novel Mutation in Intron K of the PROS1 Gene Causes Aberrant RNA Splicing and Is a Common Cause of Protein S Deficiency in a UK Thrombophilia Cohort
Authors: Daly M. E. , Makris M. , Preston F. E. , Peake I. R. , Beauchamp N. J. 
Published: March 2018

SummaryIn the course of investigating the molecular basis of protein S deficiency in 31 index cases with thrombophilia, we identified seven kindred where the underlying defect was a novel A to G transition 9 bp upstream of exon 12 in intron K of the PROS1 gene. In all but one case, the mutation caused type I deficiency. One individual had type III deficiency. While ectopic transcript analysis using the BstXI dimorphism in exon 15 failed to detect a transcript from the mutated allele, analysis of transcripts spanning exons 11 and 12 revealed a minor mRNA species. Sequencing confirmed the mutation created a new RNA acceptor site introducing 8 nucleotides of intronic sequence into the mature mRNA. Haplotype analysis of the defective PROS1 alleles in six families revealed the same haplotype in all affected individuals suggesting the presence of a common ancestor. Six of the fourteen relatives with the mutation experienced at least one venous thrombotic event strongly supporting the association of the mutation with venous thrombosis.
Low-dose Oral Vitamin K Reliably Reverses Over-anticoagulation due to Warfarin
Authors: Donovan D. , Harrison L. , McGinnis J. , Ginsberg J. , Crowther M. A. 
Published: March 2018

SummaryBackground: Patients receiving long-term warfarin frequently develop asymptomatic excessive prolongation of their international normalized ratio (INR) results. The most appropriate management strategy in these patients is unknown. This prospective cohort study was designed to address whether 1 mg of oral vitamin K effectively reduces the INR value of such patients. Methods: A prospective cohort study was performed in two tertiary care teaching hospitals, in which 62 patients receiving warfarin who had INR values between 4.5 and 10.0 received 1 mg of oral vitamin K. All patients had daily INR values and clinical assessments performed. Results: The mean INR value at presentation was 5.79 (95% confidence interval (CI) 5.48 to 6.09, range 4.5 to 9.5). Sixteen hours after receiving the 1 mg of oral vitamin K, the mean INR was 2.86 (95% CI 2.50 to 3.23). On the second and third days after vitamin K, the mean INR values were 2.20 (1.93 to 2.47) and 2.14 (1.85 to 2.44), respectively. No adverse events or bleeding complications were observed. In three patients (6%) the INR value rose between the time of vitamin K administration and the next INR determination; two patients received a further 2 mg dose of subcutaneous vitamin K. Conclusions: In patients receiving warfarin who have asymptomatic excessive prolongations in their INR results, 1 mg of oral vitamin K reliably reduces the INR to the therapeutic range within 24 h. This therapy is more convenient, less expensive, and might be safer than parenteral vitamin K. Thus, it should be considered in all non-bleeding patients receiving warfarin, who present with INR results of 4.5 to 9.5.Dr. Crowther is the recipient of a Medical Research Council of Canada Research Fellowship.Dr. Ginsberg is a Career Investigator of the Heart and Stroke Foundation of Ontario.
Activated Protein C Sensitivity, Protein C, Protein S and Coagulation in Normal Pregnancy
Authors: Brennand J. , Conkie J. A. , McCall F. , Greer I. A. , Walker Isobel , Clark P. 
Published: March 2018

SummaryA prospective study of activated protein C sensitivity, protein C, protein S, and other coagulation factors in 239 women during normal pregnancy was carried out. Protein C activity appeared unaffected by gestation, although an elevation of protein C activity was observed in the early puerperium. A fall in total and free protein S with increasing gestation was observed. Activated protein C sensitivity ratio (APC:SR) showed a progressive fall through pregnancy. This fall correlated with changes in factor VIIIc, factor Vc and protein S. 38% of subjects, with no evidence of Factor V Leiden or anticardiolipin antibodies, showed a low APC:SR (APC:SR <2.6) in the third trimester of pregnancy. Aside from a significant reduction in birth weight, no difference in pregnancy outcome was observed between these subjects and those with a normal APC:SR. Activated protein C sensitivity ratio, modified by pre-dilution of patient samples with factor V depleted plasma, showed no consistent trend with gestation.
Difference of [Ca2+]i Movements in Platelets Stimulated by Thrombin and TRAP: the Involvement of αIIbβ3-Mediated TXA2 Synthesis
Authors: Tomiyama Yoshiaki , Honda Shigenori , Senzaki Kayoko , Tanaka Akito , Okubo Mitsuru , Takahashi Fumie , Takasugi Hisashi , Seki Jiro , Aoki Toshiaki 
Published: March 2018

SummaryThis study investigated the difference of [Ca2+]i movement in platelets in response to thrombin and TRAP. The involvement of αIIbβ3 in this signaling was also studied. Stimulation of platelets with thrombin at 0.03 U/ml caused platelet aggregation and a two-peak increase in [Ca2+]i. The second peak of [Ca2+]i, but not the first peak was abolished by the inhibition of platelet aggregation with αIIbβ3 antagonists or by scavenging endogenous ADP with apyrase. A cyclooxygenase inhibitor, aspirin, and a TXA2 receptor antagonist, BM13505, also abolished the second peak of [Ca2+]i but not the first peak, although these regents did not inhibit aggregation. Under the same assay conditions, measurement of TXB2 demonstrated that αIIbβ3 antagonists and aspirin almost completely inhibited the production of TXB2. In contrast to thrombin-stimulation, TRAP caused only a single peak of [Ca2+]i even in the presence of platelet aggregation, and a high level of [Ca2+]i increase was needed for the induction of platelet aggregation. The inhibition of aggregation with αIIbβ3 antagonists had no effect on [Ca2+]i change and TXB2 production induced by TRAP. Inhibition studies using anti-GPIb antibodies suggested that GPIb may be involved in the thrombin response, but not in the TRAP. Our findings suggest that low dose thrombin causes a different [Ca2+]i response and TXA2 producing signal from TRAP. Endogenous ADP release and fibrinogen binding to αIIbβ3 are responsible for the synthesis of TXA2 which results in the induction of the second peak of [Ca2+]i in low thrombin- but not TRAP-stimulated platelets.