bluuebunny/crossref_metadata_2025 huggingface dataset:
Fixed-dose, Body Weight-independent Subcutaneous LMW Heparin versus Adjusted Dose Unfractionated Intravenous Heparin in the Initial Treatment of Proximal Venous Thrombosis
Authors: Schmidt J. A. , Koppenhagen K. , Tolle A. , Huisman M. V. , Büller H. R. , Harenberg J. ,   the EASTERN Investigators
Published: March 2018

Body weight-adjusted subcutaneous low-molecular-weight heparin (LMWH) has been proven to be at least as effective and safe as dose-adjusted intravenous unfractionated heparin (UFH) for the treatment of patients with venous thromboembolism. However, body weight-adjusted dosage of low-molecular-weight heparin may be cumbersome and could lead possibly to incorrect dosing. Therefore a fixed LMWH dose, independent of body-weight, might rationalize initial treatment for venous thromboembolism.

Patients with proven proximal deep-vein thrombosis were randomly assigned to fixed dose subcutaneous LMWH Certoparin (8,000 anti-factor Xa U b.i.d.; 265 patients) or to adjusted dose i.v. UFH (273 patients) for 12 days. Vitamin K antagonists were started between day 3 and 7 and continued for up to 6 months. The primary outcome measure was a 30 percent or greater improvement in the Marder Score, as revealed by repeated venography on day 12 (end of the initial treatment). The secondary composite outcome measure included death, recurrent venous thromboembolism and major bleeding and was assessed at day 12 and after 6 months by a blinded adjunction committee.

The Marder score improved by 30% or more in 30.3% and 25.0% of patients assigned to LMWH (198 paired venograms) and UFH (192 paired venograms), respectively (2p = 0.26). At the end of the initial treatment, the composite outcome was observed in 4 of the 265 patients (1.5%) randomized to LMWH, as compared with 14 of the 273 patients (5.1%) randomized to UFH (2p = 0.03). At 6 months these figures were 6.8% and 12.8%, respectively (risk reduction 0.53, confidence interval 0.31-0.90, 2p = 0.02).

Fixed dose subcutaneous LMWH certoparin is at least as efficacious as UFH in resolving proximal vein thrombosis. With respect to the composite outcome of death, recurrent venous thromboembolism and major bleeding LMWH treatment performed significantly better both during initial therapy and at a six-month follow-up.
Incidence of Venous Thromboembolism: A Community-based Study in Western France
Authors: Oger Emmanuel ,   the EPI-GETBO Study Group
Published: March 2018

The incidence of venous thromboembolism has been studied during one year in a defined population of 342,000 inhabitants. The overall incidence (95% confidence interval) of venous thromboembolism was found to be 1.83 per thousand per year (1.69 to 1.98). The incidences of deep venous thrombosis and pulmonary embolism were 1.24 per thousand per year (1.12 to 1.36) and 0.60 per thousand per year (0.52 to 0.69), respectively. The incidence of venous thromboembolism rose markedly with increasing age for both sexes; over the age of 75, the annual incidence reached 1 per 100. Sixty three percent of the patients were at home when venous thromboembolism occurred. Of these, sixteen percent had been previously hospitalised within three months. These results raise concerns on identification of medical patients at high risk and effective prophylaxis.
Outcome and One Year Follow-up of Intra-arterial Staphylokinase in 191 Patients with Peripheral Arterial Occlusion
Authors: Heymans Stephane , Vanderschueren Steven , Verhaeghe Raymond , Stockx Luc , Lacroix Hendrik , Nevelsteen André , Laroche Yves , Collen Désiré
Published: March 2018

Wild-type or equipotent variants of recombinant staphylokinase (rSak) were given intra-arterially (as a 2 mg bolus injection followed by an infusion of 1 mg/h or 0.5 mg/h overnight, with concomitant heparin [1000 IU/h]) to 191 patients of less than 80 years (62 ± 1 years, mean ± SEM), with a peripheral arterial occlusion (PAO) of less than 120 days (mean 14 ± 1 days, median 11 days, 5 to 95 percentiles 3 to 30 days). Ninety nine patients presented with acute or subacute ischemia, 57 with severe claudication, 33 with chronic rest pain and 2 with gangrene. Occlusion occurred in 122 native arteries and in 69 grafts. Revascularization was complete in 83 percent (158/191), partial in 13 percent (24/191) and absent in 4 percent (7/191) after administration of 12 ± 0.5 mg rSak over 14 ± 0.7 h. Complete revascularization of acute occlusions of popliteal or more distal arteries was less frequent (60 percent, 15/25) than of acute occlusions of more proximal native arteries (95 percent, 37/39, p <0.001) or grafts (89 percent, 50/56, p = 0.005). Additional endovascular procedures were performed in 47 percent and subsequent elective bypass surgery in 23 percent of patients. Major bleeding occurred in 12 percent (23/191), one month mortality was 3.1 percent (6/191) and one year mortality was 6.9 percent (12/174). However, four patients (2.1 percent) had an intracranial bleeding following therapy: a 85 year old woman with severe diabetic arteriopathy, who was included in violation of the protocol, a 79 and a 74-year-old woman and a 74-year-old man, all with severe hypertension and limb threatening ischemia; these four patients died within two months after treatment. Amputations were performed within the first year in 16 of 162 surviving patients (9.8 percent): in 7 percent (7/96) with an occluded native artery and 14 percent (9/66) with an occluded graft (p = 0.19). No significant difference in lysis rate, one month mortality or one year amputation-free survival was observed in occlusions of recent onset (<14 days, n = 126) as compared to occlusions of longer duration (<14 days, n = 65). Treatment was interrupted prematurely in 4 patients because of a suspected allergic reaction. Fibrinogen levels remained unaffected during treatment (3.3 ± 0.1 g/l before vs. 3.3 ± 0.1 g/l after infusion, n = 167).

In conclusion, rSak appears to be a highly effective thrombolytic agent in patients with PAO, resulting in a low one month mortality (3.1 percent) and a high one year amputation free survival (84 percent), with an acceptable incidence of major bleedings, but with occasional fatal intracranial hemorrhages.
Pravastatin: An Antithrombotic Effect Independent of the Cholesterol-lowering Effect
Authors: Smith Donald , Unger Allen , Shao John , Meraj Perwaiz , Fier Carl , Cohen Adam , Fallon John , Badimon Juan , Ambrose John , Dangas George
Published: March 2018

Lipid-lowering with statins reduces blood thrombogenicity. However, it is unknown whether this is purely due to LDL-cholesterol reduction, or it is related to a statin or agent specific effect. We investigated the relationship between reduction in blood thrombogenicity and the magnitude of low-density lipoprotein cholesterol (LDL-C) during pravastatin therapy.

We prospectively followed for 6 months 57 hyperlipidemic patients who initiated therapy with pravastatin, and 36 patients who were randomized into placebo plus diet. Pravastatin-treated patients were grouped according to the LDL-C reduction at 6 months; (i) “adequate LDL-C reduction”: LDL-C reduction >30% from baseline or LDL-C<125 mg/dl (n = 38; LDL-C reduction 74 ± 4 mg/dl; 6-month LDL-C 119 ± 5 mg/dl); (ii) “inadequate LDL-C reduction”: neither of the above criteria (n = 19; LDL-C reduction 31 ± 5 mg/dl; 6-month LDL-C 158 ± 6 mg/dl). Placebo patients were divided into those “with LDL-C reduction” (n = 17, mean reduction 21 ± 5 mg/dl) and those “without LDL reduction” (n = 19).

The following parameters were altered at 6 months in both patients with “adequate” and “inadequate” LDL-C reduction: (1) tissue plasminogen activator decreased by 1.4 ± 0.4 and 1.5 ± 0.5 ng/ml respectively (p = NS); (2) plasminogen activator inhibitor-1 decreased by 8.7 ± 2.0 and 10.1 ± 2.7 ng/ml respectively (p = NS); (3) thrombus formation under dynamic flow conditions decreased by 3.5 ± 0.9 and 2.8 ± 1.2 µm2 × 103 respectively (p = NS). In contrast, no significant changes from baseline were noted in placebo-treated patients, regardless of their LDL-C reduction category, and multivariate analysis eliminated LDL-C reduction as an independent predictor of reduction in thrombogenicity.

Therefore, the reduction in thrombogenicity was not proportional to the magnitude of LDL-C reduction suggesting that a class or agent specific property is primarily responsible for the pro-fibrinolytic/antithrombotic effects observed.
Protective Effects of Imidapril on He-Ne Laser-Induced Thrombosis in Cerebral Blood Vessels of Stroke-Prone Spontaneously Hypertensive Rats
Authors: Noguchi Takanori , Seki Junji , Giddings J. C. , Yamamoto Junichiro , Sasaki Yasuto
Published: March 2018

Inhibitors of angiotensin converting enzyme (ACE) have been developed recently for therapeutic purposes in hypertension and ischemic cardiovascular diseases. Ogiku et al. (1) reported that one such inhibitor, imidapril, significantly prolonged survival in stroke-prone spontaneously hypertensive rats (SHRSP). The present study was designed to investigate the effect of imidapril on cerebral blood vessels in SHRSP to clarify role of the ACE inhibitor in mechanisms of cerebral thrombosis and stroke. Imidapril was administered orally at 1.0 and 5.0 mg/kg/day for 3 weeks from the age of 7 weeks, and was shown to prevent the usual increase in blood pressure seen in these animals. It also delayed He-Ne laser-induced cerebral thrombosis and increased significantly the plasma concentration of nitric oxide metabolites (NO2/NO3). To confirm the association between nitric oxide (NO) and these effects of imidapril, an inhibitor of nitric oxide synthase, NG
- nitro-L-arginine methyl ester hydrochloride (L-NAME) was dissolved in drinking water and administered to the animals for 3 weeks. Four of six rats died from stroke when L-NAME was given alone. When imidapril (5.0 mg/kg/day) was administered with L-NAME, however, the animals showed no signs or symptoms of stroke. In these instances, therefore, the concurrent administration of L-NAME with imidapril reversed significantly the effects of imidapril. Intravenous injection of imidaprilat (100 µg/kg), an active metabolite of imidapril, also decreased blood pressure significantly and increased the plasma levels of NO2/NO3 after 5 min. Moreover, imidaprilat enlarged arteriolar diameters and caused an increase in red cell velocity and mean blood flow in pial arterioles after 15 min.

The results strongly suggested that imidapril protects cerebral vessels in SHRSP by elevating the release of NO, thereby improving the cerebral circulation and reducing the tendency to thrombosis and stroke.
Fibrinogen and Fibrin Protect Fibroblast Growth Factor-2 from Proteolytic Degradation
Authors: Sahni Abha , Baker Christopher , Sporn Lee , Francis Charles
Published: March 2018

We have recently reported that fibrinogen and fibrin bind to fibroblast growth factor-2 (FGF-2) and potentiate its ability to stimulate proliferation of endothelial cells. In the present report, we have investigated the potential of fibrinogen and fibrin to protect FGF-2 from proteolytic degradation. FGF-2 was incubated with trypsin or chymotrypsin in the presence or absence of fibrinogen or fibrin and proteolysis of FGF-2 was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. In the absence of fibrinogen there was progressive tryptic degradation of FGF-2, but in the presence of fibrinogen, FGF-2 was completely protected from trypsin with no evidence of degradation. The degree of protection was maximum at a molar ratio of FGF-2 to fibrinogen 1:2. Fibrinogen afforded similar protection from degradation by chymotrypsin. Polymerized fibrin provided partial protection of FGF-2 from tryptic degradation, with intact FGF-2 present for up to 360 min. Fibrin provided nearly complete protection from chymotrypsin. These observations indicate that binding of FGF-2 to fibrinogen or fibrin provides protection from proteolytic degradation, and this may modulate its cell proliferative activity.
Influence of SIN-1 on Platelet Ca2+ Handling in Patients with Suspected Coronary Artery Disease: Ex Vivo and In Vitro Studies
Authors: Le Feuvre Claude , Brunet Annie , Do Pham Thuc , Metzger Jean-Philippe , Vacheron André , Devynck Marie-Aude , Le Quan Sang Kim-Hanh
Published: March 2018

The 3-morpholinosydnonimine (SIN-1) generates both nitric oxide (NO) and superoxide anion (O2−). It elicits dose-dependent vasodilation in vivo, in spite of the opposite effects of its breakdown products on vascular tone and platelet aggregation.

This study was designed to investigate the influence of intravenous SIN-1 injection on platelet Ca2+ handling in patients undergoing coronary angiography. SIN-1 administration reduced cytosolic [Ca2+] in unstimulated platelets by decreasing Ca2+ influx. It attenuated Ca2+ mobilization from internal stores evoked by thrombin or thapsigargin.

In vitro studies were used as an approach to investigate how simultaneous productions of NO and O2− from SIN-1 modify thrombin- or thapsigargin-induced platelet Ca2+ mobilization. Superoxide dismutase, the O2− scavenger, enhanced the capacity of SIN-1 to inhibit Ca2+ mobilization but catalase had no effect.

This suggests that the effects of SIN-1 on platelet Ca2+ handling resemble those of NO, but are modulated by simultaneous O2− release, independently of H2O2 formation.
Systemic Endothelial Cell Markers in Primary Antiphospholipid Syndrome
Authors: Williams Frances M. , Parmar Kiran , Hughes Graham R. , Hunt Beverley
Published: March 2018

The pathogenic mechanism underlying the prothrombotic tendency of Hughes’ or antiphospholipid syndrome (APS) has not been elucidated. Numerous procoagulant mechanisms have been tested including platelet activation, monocyte tissue factor (TF) expression and endothelial cell (EC) activation. There is some evidence for the latter from studies on cultured human umbilical vein endothelial cells (HUVEC). Incubation with antiphospholipid antibodies (aPL) induces EC activation in vitro. We investigated whether there was evidence of EC perturbation in vivo using enzyme-linked immunosorbant assays (ELISAs) for soluble markers of EC dysfunction. Serum and plasma were collected from controls and patients with primary APS and ELISAs performed to quantify soluble vascular cell adhesion molecule (sVCAM), soluble intercellular adhesion molecule-1 (sICAM-1), interleukin-6 (IL-6), endothelin-1 (ET-1), von Willebrand factor (vWF) and soluble tissue factor (sTF). In addition, soluble p-selectin (p-selectin) and vascular endothelial growth factor (VEGF) were measured: the former as a marker of platelet activation, the latter as a potential mediator of TF expression. No significant differences in the levels of blood-borne soluble markers were detected between the patient and control groups except for VEGF and sTF, patients having significantly higher levels of VEGF and sTF than controls (p <0.05). These results suggest plasma soluble tissue factor and VEGF may play a role in the pathogenesis of thrombosis in APS, although the cell of origin of these molecules remains unclear.
Duration of Oral Anticoagulant Treatment in Patients with Venous Thromboembolism and a Deficiency of Antithrombin, Protein C or Protein S - A Decision Analysis
Authors: van den Belt Angelique , Hutten Barbara , Bossuyt Patrick , Prins Martin
Published: March 2018

Patients with a first venous thromboembolic event and a deficiency of the coagulation inhibitors antithrombin, protein C or protein S have an increased risk of recurrent venous thromboembolism compared to patients without such a deficiency. A decision analysis was performed to assess the effect of continuing treatment with vitamin K antagonists on mortality by a reduction in fatal recurrent pulmonary embolism and an induction of fatal haemorrhages associated with their use. The treatment decision involves continuation or discontinuation of vitamin K antagonists in patients with a first spontaneous or secondary venous thromboembolism and an antithrombin, protein C or S deficiency. Although the efficiency of oral anticoagulation is high in all age groups early after the first thromboembolic event, it decreases over time. Our analysis indicates that the optimal treatment duration will vary, depending on the type of the initial event (spontaneous or secondary; deep venous thrombosis or pulmonary embolism), age, and time passed since the initial thromboembolic episode. Moreover, life-long duration of the prophylaxis seems not warranted in all patients.
Pentoxifylline Prevents Upregulation of Monocyte Tissue Factor in Renal Transplant Recipients Undergoing Post-graft Complications
Authors: Susen Sophie , Hazzan Marc , Labalette Myriam , Zawadzki Christophe , Dessaint Jean , Lelièvre Gaston , Noël Christian , Jude Brigitte
Published: March 2018

Pentoxifylline (PTX) has been demonstrated to improve graft survival in renal transplant recipients undergoing post graft complications. As activated monocytes are possible initiators of vascular damage through tissue factor (TF) expression, we evaluated the monocyte TF expression and endothelium activation markers in 140 consecutive patients receiving cadaveric kidney grafts, randomized in a double-blind study comparing PTX versus placebo. Monocyte TF expression and plasma von Willebrand factor, tissue plasminogen activator, thrombomodulin and tumor necrosis factor-α (TNF-α) levels were determined before transplantation and each month after. Additional samplings were realized in case of acute rejection. TF and TNF-α expression were significantly modified after graft. In patients with complications, PTX prevented the increase of TF expression at month one, and after rejection episodes. Endothelium activation markers were significantly modified after graft and in patients with complications but PTX had no significant effect on their plasma levels. These results suggest that the protective effect of PTX on graft survival could be related to the prevention of monocyte TF upregulation associated with complications.
Genetic Modulation of Oral Anticoagulation with Warfarin
Authors: Colaizzo Donatella , D’Andrea Giovanna , Brancaccio Vincenzo , Ciampa Antonio , Grandone Elvira , Di Minno Giovanni , Margaglione Maurizio
Published: March 2018

Cytochrome P450 CYP2C9 gene variants have been associated with hyperresponsiveness to small doses of warfarin and a higher bleeding complication rate. The aim of this study was to investigate whether CYP2C9 gene variants affect doses of drug prescribed to acquire the target anticoagulation intensity and the occurence of bleeding complications. In a cohort of 180 patients followed up at one specialized clinic from the start of the anticoagulation with warfarin, we have investigated whether CYP2C9 gene variants have affected doses of drug prescribed to acquire the target anticoagulation intensity and the incidence of bleeding complications.

The adjusted dose required of warfarin was higher among patients with the CYP2C9*1 haplotype (5.6 mg) than those of patients carrying the CYP2C9*2 (4.7 mg; p = 0.007, Scheffé’s test) or the CYP2C9*3 haplotype (4.0 mg; p <0.001, Scheffé’s test). The occurrence of bleeding complications was more frequent among patients with the CYP2C9*2 and/or the CYP2C9*3 haplotype than in carriers of the CYP2C9*1 haplotype (OR: 2.57; 95% CI: 1.16–5.73). An interaction between the presence of local bleeding sources and the CYP2C9*2 and/or the CYP2C9*3 haplotype was observed (p <0.001). Patients with both local sites of potential bleeding and CYP2C9*2 and/or the CYP2C9*3 haplotype had the higher estimated risk of bleeding (OR: 12.81; 95% CI: 2.86–57.26).

CYP2C9 gene variants modulate the anticoagulant effect of the dose of warfarin prescribed. The incidence of bleeding complications in CYP2C9*2 and CYP2C9*3 carriers was significantly higher than that in noncarriers and interacted with the presence of local bleeding sources.
Hepatitis C Virus Transmission through Quarantine Fresh-frozen Plasma
Authors: Legler T. J. , Nübling C. M. , Riggert J. , Unger G. , Wolf C. , Heermann K.-H. , Köhler M. , Humpe A.
Published: March 2018

In 1994, quarantine fresh-frozen plasma (Q-FFP) was introduced in Germany in order to reduce the risk of HIV and HCV transmission. In 1998, an acute HCV infection of a patient was reported to us. The lookback revealed that this patient had received two Q-FFP from a donor who had seroconverted for HCV in the meantime. Recipients of further plasma donations from this donor were identified. Back-up specimens of these donations were investigated in several laboratories. A total of 25 additional HCV-PCR positive plasma units had been transfused to 12 further patients. HCV infections were diagnosed in seven of these recipients, three patients had already been deceased. One of the remaining two recipients was already HCV positive prior to transfusion, in the other patient, no HCV infection was detectable. This patient had received three units of an “early” plasma donation , which was tested negative by PCR in one laboratory, but positive in the other. The subsequent, clinically infectious donation had the same discrepant PCR results. Thus, eight cases of HCV transmission were revealed and classified as “certain” with regard to causality, also due to an identical HCV genotype, i.e. 3e. Some of these infections would have been prevented by application of a different anti-HCV assay. The assay used in the respective plasmapheresis station was in-sensitive in this individual case for more than 400 days after the first PCR positive donation. This caused the release of the above mentioned infectious units. Upon re-testing the backups, three of four other anti-HCV assays revealed a positive result already 104 days after the first PCR-positive donation. The donor had increased ALAT levels (> 23 IU/L) at nine of 28 donations, two of these were higher than 2.5 times the upper normal limit, and two were higher than 68 IU/L, which is the cut-off value for male blood donors in Germany. The results of these (look-back) studies arouse several queries, i.e. differences in the diagnostic sensitivity between current anti-HCV and PCR tests, the accuracy of risk-estimates (especially when based on hemovigilance studies for Q-FFP), the value of ALAT testing, and currently practised release algorithms for Q-FFP.
Mice Deficient in Hepsin, a Serine Protease, Exhibit Normal Embryogenesis and Unchanged Hepatocyte Regeneration Ability
Authors: Yu I.-Shing , Chen Huei-Jane , Lee Ying-Shuan , Huang Pei-Hsing , Lin Shu-Rung , Tsai Tzan-Wu , Lin Shu-Wha
Published: March 2018

Hepsin, a liver-enriched novel serine protease, has been implicated in participating with normal cell growth, embryogenesis, and blood coagulation pathway. To study its function in vivo, we have disrupted the mouse hepsin gene by homologous recombination. Targeted disruption of the hepsin gene and ablation of hepsin message were demonstrated by Southern blotting, Northern blotting and RT-PCR analysis. Homozygous hepsin −/− mice were viable, fertile, and exhibited no gross abnormalities, as judged by the size, weight and blood coagulation (PT) assays. However, the serum concentration of the bone form of alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase of the hepsin −/− mice was mildly elevated, in spite of no obvious pathological change of hepatocytes. To examine whether hepsin is involved in controlling cell growth in adult tissues, 70% hepatectomy was applied to the hepsin −/− mice. Liver regeneration proceeded normally in the hepsin −/− mice as judged by the liver mass restoration rate. These results suggest that loss of hepsin function causes no effect in cell growth and embryogenesis in vivo, which is in contradiction to the studies using in vitro cell culturing system. Moreover, gross mass regeneration of liver after damage proceeds normally in the absence of functional hepsin.
Short-term Effect of Surgical Trauma on Rat Peritoneal Fibrinolytic Activity and Its Role in Adhesion Formation
Authors: Trimbos-Kemper G. C. M. , Bakkum E. A. , Trimbos J. B. M. Z. , Declerck P. J. , Kooistra T. , Emeis J. J. , Hellebrekers B. W. J.
Published: March 2018

Fibrin deposition, the primary step in the formation of post-surgical adhesions, is the result of a disbalance between the fibrinforming and the fibrin-dissolving capacity of the peritoneum. Literature data suggest a transient reduction in local plasminogen activator activity after peritoneal trauma, which results in a reduction of fibrinolysis and permits deposited fibrin to become organized into fibrous, permanent adhesions. In the present study, the fibrinolytic parameters tissue-type plasminogen activator (tPA; antigen and activity) and plasminogen activator inhibitor type-1 (PAI-1; antigen and activity) were measured in peritoneal fluid, in peritoneal biopsies and in plasma to establish the time course of changes in fibrinolytic activity.

A standardized peritoneal adhesion model in the rat.

Analysis, over a 72-h period following surgical trauma, of the main fibrinolytic parameters in peritoneal lavage, in biopsies of damaged and undamaged peritoneum, and in plasma, and determination of fibrin and fibrin(ogen)-degradation products in peritoneal lavage fluid.

At all time intervals, tPA antigen was found to be about six-fold increased in peritoneal lavage after surgical trauma. This significant rise in tPA antigen was accompanied by a large increase in its main inhibitor PAI-1, resulting in tPA activity levels similar to, or slightly higher than, those found in control animals. tPA activity was lowest at 4 h and increased thereafter. Also in biopsies from damaged peritoneum, tPA antigen was significantly increased. Tissue tPA activity was also lowest at 4 h, after which it increased, significantly so at 24 and 72 h. Similar, though smaller, changes were seen in the biopsies from undamaged areas of the peritoneal wall in operated rats. PAI-1 (antigen and activity) was not detected in peritoneal biopsies. Fibrin-related material (especially fibrin monomer/fibrinogen, an indicator of forming fibrin) in peritoneal fluid was slightly increased at 4 h, and abundantly present at 16 and 24 h, returning to control levels at 72 h. Fibrin degradation products were always present. From 2 h onward, adhesions were found.

In contrast to the view that adhesions are formed as a result of a reduced fibrinolytic activity, our results demonstrate that tPA activity remained unchanged or slightly increased after surgical trauma, and point to increased fibrin formation rather than diminished fibrinolytic activity as the main cause of fibrin deposition after peritoneal trauma. Therapies directed at prevention of adhesion formation should therefore aim at avoiding massive fibrin production and at promoting fibrinolytic activity during the early period after trauma.
S-Nitrosoderivative of a Recombinant Fragment of von Willebrand Factor (S-Nitroso-AR545C) Inhibits Thrombus Formation in Guinea Pig Carotid Artery Thrombosis Model
Authors: Gurevitz Osnat , Eldar Michael , Skutelsky Ehud , Tamarin Ilia , Shenkman Boris , Eskaraev Regina , Castel David , Loscalzo Joseph , Inbal Aida
Published: March 2018

Antiplatelet drugs are the mainstays of therapy for acute and chronic cardiovascular diseases. S-nitroso-AR545C – an S-nitrosoderivative of a recombinant von Willebrand factor fragment AR545C spanning Ala 444 to Asp 730 and containing an Arg 545 Cys mutation, was previously found to inhibit ristocetin-and ADP-induced platelet aggregation and the interaction of platelets with extracellular matrix (ECM). In the current study we tested the antithrombotic properties of S-nitroso-AR545C on guinea pig platelets and in a platelet-rich thrombosis model in the guinea pig. Preincubation of guinea pig platelets with 0.1 µM of S-nitroso-AR545C decreased ristocetin-induced agglutination by 40% (p = 0.009) and completely abolished ADP-induced aggregation (p <0.0001). At concentration of 1.0 µM, S-nitroso-AR545C completely inhibited platelet adhesion (represented by surface coverage – SC) and decreased aggregate formation (represented by average aggregate size – AS) by more than 50%. Treatment of guinea pigs with 1.0 mg/kg S-nitroso-AR545C resulted in a significantly delayed time to arterial occlusion (31.7 ± 6.0 min vs. 13.9 ± 3.2 min, p <0.02). Similarly, total patency time was longer in the group injected with S-nitroso-AR545C compared to the control group. However, the difference was not statistically significant (33.8 ± 6.3 min vs. 20.2 ± 3.3 min, p = 0.07). No change in platelet count, hematocrit and bleeding time was observed 60 min after injection compared to baseline. In contrast, a significant decrease in SC (p <0.0001) and AS (p <0.01) were observed 60 min after the injection of S-nitroso-AR545C, whereas no change in these parameters was observed in the control group. These observations indicate that S-nitroso-AR545C exhibits significant antiadhesive and antiaggregating effects in-vitro and inhibits clot formation in-vivo suggesting that this compound may have potential therapeutic advantages.
The 536C→T Transition in the Human Tissue Factor Pathway Inhibitor (TFPI) Gene Is Statistically Associated with a Higher Risk for Venous Thrombosis
Authors: Schmidt Michael , Götting Christian , Schwenz Britt , Lange Stefan , Müller-Berghaus Gert , Brinkmann Thomas , Prohaska Wolfgang , Kleesiek Knut
Published: March 2018

Tissue factor pathway inhibitor (TFPI) is an important regulator in the extrinsic blood coagulation pathway. Although the regulatory biochemical role of TFPI is evident, the clinical significance of this proteinase inhibitor remains to be elucidated. The definition of a clinical TFPI deficiency seems to be more complex than that of other coagulation inhibitors because the activity and concentration of circulating TFPI can not be considered a true measure of in vivo levels. Its determination in plasma samples by immunological methods or functional assays has been shown to be inadequate in the detection of a clinical deficiency.

Therefore, we screened genomic DNA samples of blood donors and thrombotic patients for alterations in the TFPI gene to assess the influence of a modified TFPI in venous thromboembolic diseases. We detected a single nucleotide substitution in exon 7 (536C→T) leading to a proline to leucine exchange at amino acid position 151 of the protein ([P151L]TFPI) and found the prevalence of heterozygous carriers in German unrelated blood donors to be 0.2% (n = 5120).

Four unrelated persons out of 14 probands carrying the genetic variation could be linked to venous thrombosis. For calculation of a potential risk for venous thrombosis for carriers of the mutation we investigated healthy blood donors about thrombotic events. 7 out of 308 blood donors were found to have a history of venous thrombosis, one of them carried the TFPI mutation. Statistical calculation showed a significant relative risk for venous thrombosis for individuals with the trait (odds ratio, 9.3; confidence interval, 1.8-48.6; p <0.01).
Genetic Polymorphism of 5,10-MTHFR Reductase Gene in Offspring of Patients with Myocardial Infarction
Authors: Colaizzo Donatella , Cappucci Giuseppe , del Popolo Annamaria , Vecchione Gennaro , Grandone Elvira , Di Minno Giovanni , Margaglione Maurizio
Published: March 2018

A family history of myocardial infarction is a major determinant of ischemic disease. A C->T677 polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene has been identified as a cause of mild hyperhomocysteinemia, a risk factor for arterial thrombosis. We have investigated the relationship between the MTHFR TT genotype and a family history of myocardial infarction in a cohort of 982 apparently healthy individuals. Subjects whose first-degree relatives suffered from a myocardial infarction, showed raised median age (p <0.001), total cholesterol (p <0.001) and plasma fibrinogen (p = 0.023) and a higher than normal frequency of C-reactive protein levels >0.33 mg/dl (p = 0.012). Moreover, when compared to subjects without such family history, a higher number of homozygotes for the T allele of the MTHFR gene (p = 0.027), and of the 4G allele of the plasminogen activator inhibitor-1 gene (p = 0.002) was found in the subsetting of the offspring of patients with myocardial infarction. In a multiple logistic regression analysis, age (OR 1.02 [95%-CI: 1.00-1.05]), total cholesterol (OR 1.40 [95%-CI: 1.14-1.71]), C-reactive protein levels >0.33 mg/l (OR: 1.87 [95%-CI: 1.10-3.20]), plasminogen activator inhibitor-1 4G/4G (OR: 1.84 [95%-CI: 1.27-2.66]), and MTHFR TT genotype (OR 1.62 [95%-CI: 1.08-2.42]), were all associated with a family history of myocardial infarction. Thus, the MTHFR TT genotype independently accounts for the risk of a family history for myocardial infarction in the present setting.
Evaluation of the PFA-100® System in the Diagnosis and Therapeutic Monitoring of Patients with von Willebrand Disease
Authors: Federici Augusto , Lecchi Anna , Agati Barbara , Lombardi Rossana , Stabile Federica , Bucciarelli Paolo , Cattaneo Marco
Published: March 2018

We have evaluated platelet function at high shear with the PFA-100® system in different subtypes of von Willebrand disease (vWD), before and after the intravenous infusions of desmopressin or a factor-VIII/von Willebrand factor (vWF) concentrate. Closure times with the PFA-100® system were determined for both the collagen/ADP and the collagen/epinephrine cartridges in 52 patients with vWD (9 type 1 “platelet normal”, 5 type 1 “platelet-discordant”, 8 type 1 “platelet-low”, 6 type 2A, 9 type 2B, 6 type 2M Vicenza, 6 type 3 and 3 acquired vWD) and 40 controls. Measurements were repeated 1 and 4 h after the i.v. infusion of desmopressin (0.3 μg/Kg) in 26 patients with types 1, type 2M Vicenza or type 2A vWD, or of a factorVIII/vWF concentrate (Alphanate HT, 60 U/Kg) in 4 patients with type 3 vWD. At all time points, vWF plasma levels and the bleeding time (Symplate II) were also determined. Baseline closure times were longer in vWD patients than in controls with both the collagen/ADP and the collagen/ epinephrine cartridges. The sensitivity of the PFA-100® system (88% and 87% with the two cartridges) was higher than that of the bleeding time (65%). Treatment with desmopressin normalized the closure times in patients with type 1 “platelet-normal” or type 2M Vicenza vWD, had no significant effects in patients with type 1 “platelet-low”, type 1 “platelet-discordant” or type 2A vWD. Infusion of a factorVIII/vWF concentrate in patients with type 3 vWD slightly shortened their prolonged closure times. In general, changes in PFA-100® were paralleled by shortenings of the bleeding times and increases in plasma vWF levels. The PFA-100® test reflects vWF-dependent platelet function under high shear stress and could be useful in the diagnosis and therapeutic monitoring of patients with vWD.
Antithrombogenic Coating of Stents Using a Biodegradable Drug Delivery Technology
Authors: Herrmann R. , Schmidmaier G. , Märkl B. , Resch A. , Hähnel I. , Stemberger A. , Alt E.
Published: March 2018

To reduce the thrombogenic properties of coronary artery stents, a biodegradable polylactic acid (PLA) stent coating with an incorporated thrombin inhibitor and a platelet aggregation inhibitor has been developed. In an ex vivo human stasis model, its effect on platelets, plasmatic coagulation and its release characteristics were studied using whole blood. Bare steel and bare gold-surface stents were compared to steel and gold-surface stents coated with PLA (30 kDa) containing 5% polyethyleneglycol (PEG)-hirudin and 1% iloprost, with an empty tube as control. Markers of activated coagulation (prothrombin fragment F1-2 and thrombin-antithrombin III complex, TAT), were assayed and the release of drugs from the coating was assessed by aPTT and collagen-induced platelet aggregation. Bare steel and gold stents were completely covered by a blood clot, and high levels of coagulation markers (F1-2 fragment and TAT) were detected. No differences in the thrombogenic properties were found between bare gold or steel stents. Coated stents were free of blood clots and only minor elevations of markers were detected. Release data from in-vitro studies over 90 days showed a gradual release of the drugs with an initial exponential release characteristic for PEG-hirudin, slow release of iloprost and a 10% degradation of the PLA carrier. This drug releasing biodegradable coating effectively reduced thrombus formation independent of the metallic surface.
Adsorption of Vitamin K-dependent Proteins to Live Cell Membranes Measured under Flow Conditions
Authors: Teuschler Hoa , McGee Maria
Published: March 2018

Mechanisms mediating initial adsorption of coagulation proteins to live cells were investigated. Adsorption kinetics were examined under varying flow conditions using tracer-dilution techniques in perfused spherical monolayers of cells expressing tissue factor. At biologically relevant time and concentration ranges, rates exceeded by 2-12 fold the theoretical maximum calculated for steady-state diffusion. Rates were correlated with aqueous-phase flux of reactants and were found to be largely independent of the density of reactive sites on the membrane. Average adsorption rate of factor VIIa at 4 ηM and flow velocity of 0.8 ηm s-1 was 5 × 107 s-1 cm-2. Adsorption rates of homologous coagulation factors IX and X under similar conditions were 5 and 9 × 107 s-1 cm-2. Results indicate that flow can effectively increase the rate of coagulation factor adsorption to the membrane of live cells. They also imply that factors affecting blood flow velocity and vessel permeability influence the rate of membrane-dependent coagulation reactions.
New Assay for Measuring Binding of Platelet Glycoprotein IIb/IIIa to Unpurified von Willebrand Factor
Authors: Veyradier Agnès , Jumilly Anne-Lise , Ribba Anne-Sophie , Obert Bernadette , Houllier Anne , Meyer Dominique , Girma Jean-Pierre
Published: March 2018

Among the numerous variants of vWD, no patient with an abnormal vWF binding to GPIIb/IIIa has been described to date. To search for such potential variants, we developed a two-site assay for measuring the binding of purified GPIIb/IIIa to vWF in biological fluids and we used it to study a large series of plasmas from various types of von Willebrand disease (vWD) and recombinant vWF (rvWF).

vWF in plasma or rvWF in culture medium was immobilized onto anti-vWF monoclonal antibodies (MoAb)-coated wells of microtiter plates. After incubation with either unlabeled GPIIb/IIIa and a 125I-anti-GPIIb/IIIa MoAb or 125I-GPIIb/IIIa, binding curves and binding isotherms were respectively established. Normal pool plasma and wild-type rvWF were used as reference samples. We tested plasmas from 85 normal subjects, 115 patients with different types of vWD (64 type 1, 2 type 3, 9 type 2A, 4 type 2M, 16 type 2B, 15 type 2N, 3 type IID and 2 acquired forms) and 50 patients with various bleeding disorders. Four mutated rvWF with 2A (Glu875Lys and Pro885Ser) or 2B (Dupl.Met540 and Val551Phe) substitutions and one rvWF mutated in the RGD domain of the C-terminal part of vWF-subunit (Asp1746Gly) were also studied.

Among the various samples tested, only rvWF Asp1746Gly had no affinity for GPIIb/IIIa. In contrast, GPIIb/IIIa similarly bound to the other vWF, independently of the proteic environment, the factor VIII level, the degree of multimerization or the mutation of vWF. Our results indicate that subjects with an abnormal vWF binding to GPIIb/IIIa are probably rare and difficult to target for a specific screening.
Increased Levels of Tissue Factor mRNA in Mononuclear Blood Cells of Patients with Primary Antiphospholipid Syndrome
Authors: López-Pedrera Chari , Velasco Francisco , Aguirre María , Torres Antonio , Cuadrado María , Dobado-Berrios Pablo
Published: March 2018

Antiphospholipid antibodies (aPL) may stimulate tissue factor (TF) expression in cultured endothelial cells and monocytes, but there are discrepancies as to the expression of TF in the patients with antiphospholipid syndrome (APS). By using reverse transcription and polymerase chain reaction amplification, we have analysed TF mRNA accumulation in freshly isolated mononuclear blood cells (MBC) of 14 patients with primary APS (PAPS) and six normal controls. TF mRNA accumulation was low or absent in uncultured MBC from all normal controls, but was elevated in uncultured MBC from nine of the patients as well as in normal MBC incubated with 100 ng/ml lipopolysaccharide (LPS). Mean levels of TF mRNA, as measured by densitometry, were higher in MBC from patients (N = 14) than in those from controls (N = 6, P = 0.009), and in MBC from patients with a history of thrombosis (N = 9) than in those from patients without thrombosis (N = 5, P = 0.02). Uncultured MBC of patients with thrombosis accumulated TF mRNA at similar levels to LPS-treated normal MBC. Increased levels of TF mRNA were found in eight of ten patients with conventional aPL (ie, anti-cardiolipin antibodies [aCL] and/or lupus anticoagulant [LA]) and littleif any accumulation of TF mRNA was observed in three of four patients without aPL at the time of study. These data strongly suggest that circulating monocytes of many patients with PAPS are subjected to an up-regulated TF expression that may well explain their prothrombotic state. Although the presence or absence of TF mRNA in MBC was associated with, respectively, the presence or absence of conventional aPL in 11 of the 14 patients studied, our study cannot exclude the involvement of factors other than aCL or LA in inducing TF expression.
Multicenter, Randomized, Comparative Study of Recombinant vs. Natural Streptokinases in Acute Myocardial Infarct (TERIMA)
Authors:   The TERIMA Group Investigators
Published: March 2018

Aim: To compare the effects on hemostasis and coronary patency of recombinant (rSK) and natural (nSK) streptokinases in patients with acute myocardial infarct (AMI). Methods: Patients from 7 hospitals, <70 years old, less than 12 h after the onset of AMI symptoms, with ST segment elevation or bundle branch block, without contraindications for thrombolytic therapy, were randomized to receive 1.5 million units of nSK or rSK in a one-hour intravenous infusion. Fibrinogen, fibrinogen degradation products (FDP) and thrombin time were monitored. A coronary angiography was performed after 5-10 days in those patients who gave their consent and did not refer allergy to iodine contrasts. Images were blindly evaluated by an independent committee. Results: 224 patients were randomized (113 nSK and 111 rSK). Groups were equivalent in all baseline and demographic variables except that rSK patients were 5.4 years significantly older. They were also comparable in all the clinical characteristics. Both treatments produced the same changes in hemostasis. Fibrinogen levels decreased, FDP and thrombin time increased immediately after thrombolysis and returned to baseline 2 days afterwards, but fibrinogen values continued to increase up to day 10. Coronary patency (TIMI 2-3) rates at 7.8 ± 2.7 and 8.0 ± 2.7 days after fibrinolysis were 70.7% and 67.1% for nSK and rSK groups, respectively (non-significant difference). Hypotension and arrhythmias were the most frequent adverse events in both groups, which did not differ in this respect either. Five patients from each group died, one of them (nSK) due to gastroduodenal bleeding probably related to treatment. Conclusions: rSK behaved similarly to nSK regarding coronary patency at 8 days after thrombolysis and the changes induced on fibrinogen, FDP and thrombin time. These results suggest that the same benefit/risk profile reported for AMI patients treated with nSK can be expected for rSK.

A list of the “Trombolisis con Estreptoquinasa Recombinante en el Infarto del Miocardio Agudo” (Thrombolysis with Recombinant Streptokinase in Acute Myocardial Infarct) investigators appears in the Appendix, p. 1608.
Monocyte Tissue Factor Expression Is Enhanced in Women who Smoke and Use Oral Contraceptives
Authors: Terhalle Helma-Meta , Zakel Ute , Maus Ulrich , Parviz Behnoush , Tillmanns Harald , Haberbosch Werner , Hölschermann Hans
Published: March 2018

The association between use of oral contraceptives (OCs) and increased risk of thromboembolic disease has been firmly established. This risk increases when use of OCs is combined with cigarette smoking. The cellular mechanism favoring an hypercoagulable state under these behaviours is not known. Circulating monocytes are potent activators of the coagulation cascade through their ability to synthesize procoagulant tissue factor (TF). In the present study we report that monocyte TF expression is increased in women who use OCs and smoke.

We studied monocyte TF expression in 4 groups of healthy pre-menopausal women (n = 15 each): (1) non-smoking OC non-users, (2) nonsmoking current OC users, (3) smoking OC non-users and (4) smoking OC users. TF expression was assessed on both mRNA and protein levels in unstimulated and LPS-stimulated cells. Transcriptional activation of the TF gene was assessed by analysis of the transcription factor NF-κB and its inhibitor molecule IκBα. Monocyte TF generation was significantly higher in OC users than in women who did not use OCs. Enhanced monocyte TF generation was also observed in smoking women when compared to non-smokers. Strongest monocyte TF expression occurred in women with combined smoking and use of OCs. The enhanced TF expression in monocytes from women using OCs or smoking was based on an increased TF gene transcription following activation of NF-κB. Experiments on cultured monocytes/macrophages demonstrated enhanced IκBα degradation in the presence of estradiol, suggesting that a direct hormone effect is responsible for the observed increase in monocyte TF expression.

This study demonstrates that use of OCs and smoking is associated with an increase in monocyte TF expression in pre-menopausal women. Aberrant TF expression by blood monocytes may favour intravascular clotting activation in women with OC therapy. The further enhancement of TF activity observed in women who smoke and use OCs may explain the synergistic effect of smoking on risk of thromboembolic events associated with contraceptive use.
In Vitro Characterisation of Two Naturally Occurring Mutations in the Thrombin-sensitive Region of Anticoagulant Protein S
Authors: Giri Tusar , de Frutos Pablo García , Yamazaki Tomio , Villoutreix Bruno , Dahlbäck Björn
Published: March 2018

The molecular consequences of two naturally occurring mutations in the thrombin-sensitive region of protein S were investigated using a combination of recombinant protein expression, functional analysis and molecular modelling. Both mutations (R49H and R70S) have been found in thrombosis patients diagnosed as having type I protein S deficiency. Molecular modelling analysis suggested the R49H substitution not to disrupt the structure of thrombin-sensitive region, whereas the R70S substitution could affect the 3D structure mildly. To elucidate the molecular consequences of these substitutions experimentally, site directed mutagenesis of protein S cDNA and expression in mammalian cells created the two mutants. The secretion profiles and functional anticoagulant activities of the protein S mutants were characterised. Secretion of the R49H mutant was similar to that of wild type protein S, whereas the R70S mutant showed moderately decreased expression. Neither of the mutants showed any major functional defects as cofactors to activated protein C (APC) in an APTT-based assay or in degradation of factor Va. However, both mutants demonstrated decreased activity in a factor VIIIa degradation assay, which in addition to APC and protein S also included factor V as synergistic APC cofactor. In conclusion, the R49H substitution did not produce a quantitative abnormality in vitro, raising doubts as to whether it caused the type I deficiency. In contrast, the experimental data obtained for the R70S mutant agrees well with the observed type I deficiency. Our study illustrates that in vitro experimental characterisation together with computer-based structural analysis are useful tools in the analysis of the relationship between naturally occurring mutations and clinical phenotypes.