bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the Molecular Basis for the Virulence of Escherichia coli K5 by Nuclear Magnetic Resonance Analysis of the Capsule Polysaccharide
Authors: Blundell Charles D. , Roberts Ian S. , Sheehan John K. , Almond Andrew
Published: April 2009

The capsular polysaccharide of Escherichia coli K5 has been hypothesised to promote virulence through its molecular mimicry of host heparan sulphate. To test this hypothesis, we have produced pure oligosaccharides from K5 capsular polysaccharide and investigated their conformational properties with ultra-high-field nuclear magnetic resonance (NMR) (900 MHz). Ultra-high-field affords a significant resolution enhancement over previous studies and allowed a full-atomic assignment of the K5 hexasaccharide for the first time. All carbohydrate rings adopt a 4C1 conformation, the amide sidechains have a trans orientation and the hydroxymethyl group is freely exposed to bulk solvent. Initial models of the glycosidic linkage conformation based upon simple interpretation of NOE cross-peaks suggests that the β1→4 linkage adopts a 3D geometry of φ ≈ 60°, ψ ≈ 0° and the α1→4 linkage prefers φ ≈ –30°, ψ ≈ –30° (φ and ψ being defined by dihedral angles involving linkage protons). In this conformation the overall molecular geometries of K5 polysaccharide, heparan sulphate and even fully-sulphated heparin are remarkably similar. These results substantiate the hypothesis that the K5 capsular polysaccharide confers virulence to E. coli K5 by being a 3D molecular mimetic of host heparan sulphate, helping it to evade detection by the mammalian immune system.
Factor XIII of Blood Coagulation Modulates Collagen Biosynthesis by Fibroblasts in vitro
Authors: Paye M. , Nusgens B.V. , Lapière C.M.
Published: April 2009

The effect of activated factor XIII (FXIIIa), the transglutaminase of blood coagulation, on some cellular functions was studied in skin and lung fibroblasts in vitro. FXIIIa repressed the overall protein synthesis and mainly collagen synthesis in a concentration-dependent manner and induced modifications in the proportion of the different types of newly synthesized collagen. The repression of collagen synthesis occurred in cells cultured on plastic (-40%), on coated fibronectin (-53%), on coated collagens (-38%) and within a collagen lattice (-16%). Preincubation of the cells with FXIIIa and labelling in its absence also resulted in such an inhibition. However, when embedded into a fibrin lattice cross-linked by FXIIIa, fibroblasts displayed a higher biosynthetic activity than in untreated fibrin gel. These results suggest that FXIIIa acts through a modulation of the cell-matrix interactions.
Computerized Analysis of the in vitro Activation of the Plasmatic Clotting System
Authors: Baumann Peter , Jürgensen Thomas , Heuck Claus-Ch.
Published: April 2009

We analyzed the kinetics of the clotting system by a chromogenic substrate method in plasma with isolated factor deficiency. The sigmoidal extinction curve obtained was mathematically described by an equation with four constants K(i) relating to the activity of clotting factors and to the concentration of fibrinogen. The analysis of constants obtained from dilution series of factor-deficient plasma revealed a distribution pattern differing from one factor to another both for the extrinsic and the intrinsic system. The observations indicated that isolated factor deficiency may be identified through the analysis of 2 of the 4 constants, K(1) being the time value of the point of inflection of the extinction curve and K(2) a measure for the slope of the curve at the point of inflection. The observation was confirmed by a reclassification through nearest-neighbor discriminant analysis of K(1) and K(2) which revealed a correct classification in the pathological range for all factor deficiencies investigated with the exception of factors VIII and IX, the distribution patterns of which were superposed within the limits of distribution.
Fibrinolytic and Amidolytic Activities of Elastase- and Chymotrypsin-Like Proteases in Spleen and Leukocytes of Some Mammals
Authors: Nagamatsu Y. , Okamoto U. , Yamamoto J. , Tsuda Y. , Okada Y.
Published: April 2009

Nonplasmin-mediated fibrinolytic activities were extracted with 2 M NaClO4 from the spleen and leukocytes of nine species of mammals. The amidolytic and fibrinolytic activities of extracts were measured using Suc-Ala-Tyr-Leu-Val-pNA for elastase-like protease (ELP) and Suc-Tyr-Leu-Phe-pNA (or Suc-Ile-Pro-Phe-pNA) for chymotrypsin-like protease (CLP). ELP and the fibrinolytic activity in the human spleen and leukocytes exhibited the highest values among the nine species. The relative order of amidolysis by CLP was as follows: hamster& > rat& > mouse& > dog in the spleen and hamster& > rat = ox& > dog in leukocytes. Neither fibrinolytic nor amidolytic activity was measurable in spleens and leukocytes of pigs and rabbits. The ratios of ELP to CLP activity in the spleen or leukocytes of each of the species varied significantly from those observed in humans. The amidolytic activity of the spleen in control mice was low; however, that of mice which had been intraperitoneally inoculated with sarcoma 180 cells was enhanced and further accompanied by an increase in the number of granulocytes and in fibrinolytic activity. These results suggest that the enhancement of spleen amidolytic and fibrinolytic activites is induced by an increase of granulocytes in the circulation.
Fatal Thrombotic Thrombocytopenic Purpura despite Plasmapheresis
Authors: Kwaan Hau C. , Domer Peter H.
Published: April 2009

Thrombotic thrombocytopenic purpura (TTP) is a syndrome characterized by microangiopathic hemolytic anemia, thrombocytopenia, neurologic abnormalities, fever and renal dysfunction. Prior to modern therapy, fewer than 3% of patients survived. However, with plasmapheresis, up to 82% of patients survive. We report a case of recurrent TTP which proved fatal despite plasmapheresis. At autopsy the hyaline thrombi found were notably smaller and of shorter duration than those of untreated TTP. These findings suggest that therapy had brought about an abatement of the microthrombotic process in spite of the fatal outcome.
Carriership for Homocystinuria in Juvenile Vascular Disease
Authors: Boers G.H.J.
Published: April 2009

The frequency of pathological homocysteine accumulation after standardized methionine loading was investigated in 75 patients with clinical signs of ischemic disease before age 50: 25 with occlusive peripheral arterial disease, 25 with occlusive cerebrovascular disease, and 25 with myocardial infarction. On the basis of abnormally high homocysteinemia after methionine loading and cystathionine synthase deficiency in fibroblast cultures, carriership for homocystinuria could be established in 7 patients in each of the first two groups, however in none of the patients in the third group. This high frequency of heterozygosity compared with the frequency of 1 in 70 at the most in the normal population leads to the conclusion that such carriership predisposes to the development of premature occlusive arterial disease.
Plasma Homocysteine and Methionine Tolerance in Early-Onset Vascular Disease
Authors: Brattström Lars , Israelsson Bo , Hultberg Björn
Published: April 2009

In three different studies we tested the hypothesis that early-onset vascular disease is associated with impaired homocysteine metabolism which could contribute to the development of arteriosclerosis and thrombosis. In patients with occlusive vascular disease before the age of 60, a post-methionine load increase of plasma homocysteine exceeding the highest value for comparable healthy control subjects was found in 1 of 21 with myocardial infarction (5%), 14 of 37 with aorto-iliac disease (38%), and 17 of 53 with cerebrovascular disease (32%). This might indicate heterozygosity for homocystinuria due to cystathionine β-synthase deficiency. Concentrations of serum vitamin B12 and red cell folate had an important modulating effect on plasma homocysteine concentrations in the fasting state.
1-Deamino-8-D-Arginine Vasopressin in the Treatment of Non-Haemophilic Patients with Acquired Factor VIII Inhibitor
Authors: Muhm M. , Grois N. , Kier P. , Stümpflen A. , Kyrle P. , Pabinger I. , Bettelheim P. , Hinterberger W. , Lechner K.
Published: April 2009

1-Deamino-8-.D-arginine vasopressin (DDAVP) was administered to 3 patients with spontaneous factor VIII inhibitors. In 2 patients with baseline factor VIII levels above 1 %, a marked increase of factor VIII activity after DDAVP infusion could be observed. No rise of factor VIII activity after DDAVP was seen in the 3rd patient with a baseline factor VIII level of less than 1 %. Daily infusion of DDAVP resulted in a reduction of the efficacy, but the full effect could be retained when DDAVP was given at 48-hour intervals. The effect of DDAVP infusion on factor VIII levels in the 2 responding patients was superior to the treatment with 30 U/kg factor VIII concentrate and approximately equivalent to infusion of 45 U/kg factor VIII concentrate. DDAVP may be a useful and less expensive treatment for patients with acquired factor VIII inhibitors and a baseline factor VIII level of more than 1 %.
Algorithm for Short-Term Prescription of Phenprocoumon
Authors: Heaf James , Guldager Bernadette
Published: April 2009

Data from the start of anticoagulation therapy using the coumarin derivative phenprocoumon were obtained retrospectively for 101 patients, and the correct long-term maintenance dose (MD) of the drug was determined. The average loading dose was 23.2 ± 7.8 mg and the average MD 2.14 ± 0.99 mg. The physician’s prescription on discharge tended to underestimate the true MD by 0.29 ± 0.64 mg. Significant positive correlations with MD were noted for loading dose and weight and negative correlations for age, serum creatinine, initial prothrombin ratio, and length of treatment pause (days) for patients receiving an excessive loading dose. Using stepwise variance analysis, an algorithm was obtained that predicted the MD: MD = -0.7 + loading dose/10 – treatment pause/7 – age/60 + initial prothrombin ratio. The accuracy (0.02 ± 0.54 mg) was similar to that of the discharging physician. The algorithm required an average observation period of 5.4 days and the physician’s estimate 12.4 days. It is suggested that the use of the algorithm would lead to shorter hospitalization without loss of treatment accuracy.
Increased Activity of Factor VII and Factor VII-Phospholipid Complex Measured Using a Normotest System in Subjects with Hyperlipidemia
Authors: Nordøy A. , Illingworth D.R. , Connor W.E. , Goodnight, Jr S.
Published: April 2009

Coagulation factor VII and factor VII-phospholipid complex (factor VIIp1), an activated form of factor VII, were measured using a Normotest system in 128 patients with various types of hyperlipoproteinemias and in 45 control subjects. A positive correlation was found between both factors VII (p < 0.001) and VIIp1 (p < 0.0001) and serum triglycerides. Similar correlations were established with very low density lipoproteins. A positive correlation was also observed between factor VIIpι and total cholesterol, whereas inverse correlations were found with high-density lipoproteins for both factors VII and VII p1• No positive correlation could be found between low-density lipoproteins and factors VII and VIIp1• This study has shown that patients with hyperlipoproteinemias associated with high serum triglyceride levels, with or without high cholesterol levels, have increased activity of factors VII and VIIp1, both previously associated with an increased risk of coronary heart disease.
Anticoagulant and Antithrombotic Effects of Chemically Modified Heparins and Pentosanpolysulfate
Authors: Krupinski K. , Breddin H.K. , Casu B.
Published: April 2009

Pig mucosal heparin (GAG 98), in which the binding site for antithrombin had been inactivated by periodate oxidation (GAG 262), a supersulfated low-molecular-weight heparin (GAG 869), a low-molecular-weight heparin (Fragmin®), and sodium pentosanpolysulfate have been investigated on their anticoagulant effects in vitro and ex vivo and in an animal thrombosis model in which rat mesenteric venules are damaged by defined laser energy. GAG 262 and pentosanpolysulfate had a markedly reduced anticoagulant effect compared to heparin, Fragmin, and the supersulfated low-molecular-weight heparin fragment. Similarily, the doses necessary to inhibit thrombus formation in the laser model were much higher for GAG 262 and for pentosanpolysulfate compared to heparin and the low-molecular-weight heparin Fragmin, but much lower for the supersulfated heparin fragment. The antithrombotic effect of the low-molecular-weight heparin Fragmin and the supersulfated heparin fragment after subcutaneous injection lasted much longer than the ex vivo detectable anticoagulant effect. Although some correlation between the antithrombotic and the anticoagulant effect in the laser model is evident, there seems to be no direct correlation between amount and duration of factor IIa or factor Xa inhibition and extent and duration of the inhibition of thrombus formation.
Elevated Platelet Activation in Type I Diabetics with Chronic Complications under Long-Term Near-Normoglycemic Control
Authors: Tschoepe D. , Ostermann H. , Huebinger A. , Ziegler D. , Wiefels K. , Gries F.A.
Published: April 2009

A prethrombotic state with altered, hyperactive platelets may contribute to the development of diabetic late complications. Whether increased platelet ‘in vivo’ activation can be reduced by tight metabolic control is controversial. We studied plasma markers of platelet activation in 64 long-term, microangiopathic type I diabetics after at least 18 months of intensive treatment for near-normoglycemia. Both platelet factor 4 and β-thromboglobulin proved to be significantly (p ≤ 0.05) elevated in comparison with healthy controls: 15.8 (sdf 2)/77.6 (sdf 1.9) vs. 8.9 (sdf 1.6)/45.1 (sdf 2) ng/ml (sdf = standard deviation factor). We found no significant correlations with any metabolic parameter (actual blood glucose, mean blood glucose, HbA 1 triglycerides, cholesterol) or with the duration of intensive treatment. It is therefore concluded, that platelet ‘in vivo’ activation takes place in type I diabetics even after long-term near-normoglycemic control. This deviation could be regarded as indicator of an additional risk for the development of vascular complications.
Aspirin at Very Ultra Low Dosage in Healthy Volunteers: Effects on Bleeding Time, Platelet Aggregation and Coagulation
Authors: Doutremepuich C. , de Sèze O. , Le Roy D. , Lalanne M.C. , Anne M.C.
Published: April 2009

Aspirin at very ultra low dosage was tested in healthy volunteers (n = 20) in a randomized, double-blind and placebo-controlled trial. The results showed a bleeding time reduction (p < 0.05) in volunteers having previously ingested aspirin. Platelet aggregation on platelet-rich plasma was not statistically modified after aspirin ingestion. Thrombin clotting time was always higher (p < 0.05) in the treated group.
Effect of Quinidine on Platelets
Authors: Chong B.H. , Kaplin I.J.
Published: April 2009

The effects of quinidine on platelets over a wide range of concentrations of the drug were studied. It was found that quinidine at high concentrations (1 and 1.5 mM) induced platelets to undergo profound ultrastructural changes and 14C-serotonin release. In addition, the drug at these concentrations caused marked inhibition of platelet aggregation mediated by adenosine diphosphate, adrenaline, collagen and arachidonate but had no effect on ristocetin-induced agglutination. However, quinidine at 10 μM (a pharmacological concentration) had only a variable inhibitory effect on adrenaline-induced platelet aggregation.
Heparin-Related Osteoporosis in Rats
Authors: Monreal M. , Viñas L. , Monreal L. , Lavin S. , Lafoz E. , Angles A.M.
Published: April 2009

In an animal model, the effect of a high dose of conventional heparin (2 IU/g s.c. twice a day) and a low-molecular-weight heparin (LMWH; Fragmin, 1 anti-Xa U/g once a day) was compared with that of placebo on the mineral bone mass in the femur of rats. After 33 days of treatment no differences were found in the weight of the femur. But heparin-treated rats exhibited a lower density (1,249 ± 0.046 g/ml as compared with that in control rats (p = 0.00007) and also in LMWH-treated rats (p = 0.001). Similarly, statistically significant differences have been found in ash contents. They were higher in control rats than in heparin-treated rats (p = 0.0002), and also slightly higher than in LMWH-treated rats (p = 0.01). Our findings suggest that LMWH may have a lower osteopenic effect than that of conventional heparin.
Enhanced Ristocetin-Induced von Willebrand Factor Binding to Platelet Glycoprotein lb in Patients with Steroid-Responsive Nephrotic Syndrome
Authors: Taira Koji , Kamitsuji Hidekazu , Okajima Chikako , Fujimura Yoshihiro
Published: April 2009

To elucidate the mechanism of enhanced ristocetin-induced platelet aggregation (RIPA) in steroid-responsive nephrotic syndrome (SRNS), plasma levels of von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor (RCof) were examined in 6 patients and the amount of ristocetin-induced vWF binding to platelets was determined. At the initial or relapse stage, the plasma vWF:Ag level was 415 ± 137% and the RCof level was 364 ± 1.17%. The ratio of RCof/vWF:Ag was 0.90 ± 0.15 and no abnormalities of vWF:Ag multimers were observed, indicating that neither functional nor structural abnormalities were present in patient’s plasma. The amount of ristocetin-induced normal vWF binding to nephrotic washed platelets, when ristocetin was used at concentrations of 0.5, 0.75, and 1.0 mg/ml, was 152–163% above the binding to normal platelets. In addition, nephrotic washed platelets resuspended in either normal or nephrotic plasma aggregated at a low concentration of ristocetin (0.75 mg/ml) which did not induce aggregation of normal platelets. In accordance with these observations, the decrease of Alcian blue 8GX binding to platelets, reflecting diminished surface negative charge, was also observed. These results appear to indicate that the plasma vWF level and the altered surface-negative charge in platelets both contribute to heightened vWF binding to GPIb, thus lowering the ristocetin concentration required for RIPA in SRNS.
Effect of Orchidectomy on Tissue Plasminogen Activator Activity, Plasminogen Activator Inhibition and Plasmin Inhibition
Authors: Kokolis N.A.
Published: April 2009

The effect of unilateral or bilateral orchidectomy on tissue plasminogen activator activity (PAA), plasminogen activator inhibition (PAI) and plasmin inhibition (PI) was studied in the rat. Orchidectomy was performed in young or adult rats. Unilateral orchidectomy affected only PI in the lungs and brain, 1, 2 and 3 months after orchidectomy was performed in adult rats. Bilateral orchidectomy performed in young or adult rats affected one or more of the parameters studied in one or more of the key organs (brain, lungs, kidneys, heart, aorta), in most cases only 2 and 3 months after orchidectomy. Therefore, the effect of orchidectomy on tissue PAA, PAI or PI was variable and dependent on the extent of the orchidectomy (unilateral or bilateral), the age of the animal at orchidectomy, the time after orchidectomy, and the organ.
Glycometabolic Control and Fibrinolysis in Diabetic Patients
Authors: van Wersch J.W.J. , Westerhuis L.W.J.J.M. , Venekamp W.J.R.R.
Published: April 2009

We investigated 148 diabetic patients with regard to their relationship between fibrinolysis (D-dimer and plasminogen activator inhibitor; PAI) and glycometabolic control (HbA1c, HbA1 and fructosamine). The percentage of moderately controlled patients as indicated by HbA1c, HbA1 and fructosamine is relatively high (29.7, 41.7 and 30.4%, respectively). Simultaneously, the D-dimer and PAI levels turned out to be enhanced in 30.8 and 22.4% of the patients. There was a positive nonsignificant correlation between D-dimer and HbA1c, a highly significant negative correlation between D-dimer and HbA1 and a nonsignificant negative correlation between D-dimer and fructosamine. According to the upper limits of the distinct reference ranges for HbA1c, HbA1 and fructosamine, we splitted up the .D-dimer results and calculated the mean D-dimer values belonging to each category. Comparing the D-dimer means for each parameter, we separately obtained significant differences of the D-dimer means between the lower and higher HbA1 and fructosamine groups, whereas in the case of HbA1c the mean D-dimer values of the categories under and over 9% showed no significant difference. For PAI, we found only weak nonsignificant positive correlations to D-dimer and fructosamine and weak but highly significant correlations to HbA1c. These results are indicative for an increase of PAI with diminished glycometabolic control as measured with the HbA1c and fructosamine level. Both D-dimer and PAI showed positive, highly significant correlations to the age of the diabetic patients, whereas HbA1c and fructosamine were age independent. The results described in this report demonstrate that the fibrin degradation to D-dimer fragments by the specific fibrinolytic enzyme plasmin is dependent on the glycometabolic control state as measured with HbA1 and fructosamine and thus on the nonenzymatic glycosylation, which reduces the susceptibility of fibrin to degradation by plasmin.
Indices of Hypercoagulation in Cancer as Compared with Those in Acute Inflammation and Acute Infarction
Authors: Lindahl Anne Karin , Sandset Per Morten , Abildgaard Ulrich
Published: April 2009

The mean levels of fibrinopeptide A (FPA), thrombin-antithrombin complex (TAT), and soluble fibrin (tPA method) in cancer patients (n = 32) were intermediate between those of patients with cerebral infarction and pancreatitis who had the most abnormal results and patients with myocardial infarction and pneumonia who had the least abnormal results. Patients with disseminated malignancies (n = 16) had significantly higher mean levels of FPA (10.6 vs. 5.3 nmol/l) and TAT (11.0 vs. 4.4 pmol/l) than patients with limited malignancies (n = 16). The difference in soluble fibrin (fibrin monomer, FM; 22.1 vs. 18.0 nmol/l) was not significant. The values of FPA, FM, and TAT in the patient population correlated significantly. There was a negative correlation between the level of antithrombin and test results for FPA (-0.69), FM (-0.48), and TAT (-0.38) in the cancer patients. Even cancer patients with locally limited disease may have elevated FPA, FM, and TAT test results, indicating a state of definite hypercoagulation.
Interaction between Nabumetone – a New Non-Steroidal Anti-Inflammatory Drug – and the Haemostatic System ex vivo
Authors: Al Balla S. , Al Momen A.K. , Al Arfaj H. , Al Sugair S. , Gader A.M.A.
Published: April 2009

Twenty-six healthy volunteers were given the non-steroidal anti-inflammatory drug nabumetone (1 g/day p.o.) for 10 days. Platelet aggregation tests in response to adenosine diphosphate, adrenaline, collagen, arachidonic acid, and ristocetin and bleeding time and coagulation screening tests were performed on three occasions: (1) before drug therapy; (2) on the last day of drug therapy, and (3) 5 days after the end of therapy. No significant changes were noted in platelet aggregation, bleeding time, or the coagulation screening tests, except for a significant drop in fibrinogen during therapy and for 1 week after stopping the drug. The lack of any antiplatelet action and minimal effects on the coagulation parameters recommend the drug as a suitable antirheumatic in patients with bleeding disorders. The hypofibrinogenaemic action requires further studies.
Effect of Cerastobin, a Thrombinlike Enzyme from Cerastes vipera (Egyptian Sand Snake) Venom, on Human Platelets
Authors: Farid Taker M. , Tu Anthony T. , El-Asmar Farid
Published: April 2009

Cerastobin, a thrombinlike enzyme with arginine esterase activity, was purified from crude Cerastes vipera (Egyptian Sahara snake) venom. Unlike thrombinlike enzymes isolated from other snake venoms, cerastobin had a potent platelet aggregatory effect. The activation of human platelets was not related to adenosine diphosphate release and/or prostaglandin synthesis. Cerastobin showed a proteolytic activity towards protein constituents of the platelets’ cytoskeleton. It hydrolyzed actin, actin-binding protein, and P235. This may explain at least a part of the aggregatory mechanism(s) of cerastobin. Electron microscopic studies of the stimulated platelets revealed changes in their morphology, including the appearance of pseudopodia, dilatation of the canalicular system with the formation of peripheral balloons, and centralization of the platelet organelles. Some inhibitors of the esteratic activity of cerastobin also inhibited its ability to aggregate platelets.
Changes in Plasminogen Activator Inhibitor 1 and Tissue-Type Plasminogen Activator during Exercise in Patients with Coronary Artery Disease
Authors: Rydzewski Andrzej , Sakata Kazuyuki , Kobayashi Akira , Yamazaki Noboru , Urano Tetsumei , Takada Yumiko , Takada Akikazu
Published: April 2009

As depressed fibrinolysis is implicated in the pathogenesis of coronary artery disease, we have studied the activation of fibrinolysis during maximal, symptom-limited exercise in a group of 68 men. After exercise they were divided, according to their coronary angiography and exercise 201T1 emission computed tomography results, into three groups. Group 1: persons with normal exercise 201T1 emission computed tomography results and no underlying diseases who served as controls; group 2: patients with coronary artery disease without exercise-induced myocardial ischemia, and group 3: patients with coronary artery disease with transient, exercise-induced myocardial ischemia. Before and at peak exercise we measured the plasminogen activator activity (PAA) in the euglobulin fraction of plasma by an amidolytic method and the concentrations of tissue plasminogen activator (t-PA), activator-inhibitor complex – plasminogen activator inhibitor 1 (PAI-1) complexed with t-PA -and total PAI-1 by enzyme immunoassay. The concentration of free PAI-1 in plasma was calculated by subtraction of the concentration of activator-inhibitor complex from that of total PAI-1. Under basal conditions, group 3 had significantly higher free and total PAI-1 levels than group 1. There were no statistically significant differences between the three groups in PAA, t-PA, and activator-inhibitor complex levels. At peak exercise, group 1 showed the highest release of t-PA accompanied with highest increases in PAA as well as in activator-inhibitor complex, the proportion of released t-PA antigen not bound to PAI-1 being highest in group 1. Free PAI-1 decreased significantly, but there were no differences between individual groups. Our results indicate that increased PAI-1 levels in plasma and decreased release of t-PA from endothelial stores play a role in impairment of fibrinolysis in coronary artery disease. These disturbances are more pronounced in patients who develop myocardial ischemia during exercise.
Female Sex Hormones and Platelet/Endothelial Cell Interactions
Authors: Nordbø Berge Lillian , Hansen John-Bjarne , Svensson Birgit , Lyngmo Vegard , Nordøy Arne
Published: April 2009

The effects of estradiol and progesterone added to the growth medium of human umbilical vein endothelial cells for 72 h on the formation and release of prostacyclin were investigated. The influence on collagen-induced platelet aggregation and on the platelet formation of thromboxane A2 following aggregation, of the growth medium collected before and after thrombin stimulation of the endothelial cells, was studied simultaneously. Under basal conditions, endothelial cells grown with progesterone released significantly less prostacyclin into the growth medium than did controls (p < 0.05). Following thrombin stimulation, endothelial cells grown with estradiol (p < 0.05) or a combination of estradiol and progesterone (p < 0.01) contained significantly less prostacyclin than controls. No significant effects on the platelet aggregation or platelet thromboxane formation could be found. This study indicates a lowering effect of both female sex hormones on the endothelial cell prostacyclin formation and release. This may be of significance for the increased risk of vascular disease in pregnant women and oral contraceptive users, but can hardly explain the consequences of the hormonal loss occurring at the menopause.
Antigen Levels of Plasminogen Activator Inhibitor Type 1 in Citrated Plasma: Determination of the Contribution of Platelets
Authors: Grimaudo V. , Bachmann F. , Kruithof E.K.O.
Published: April 2009

To estimate the extent of the release of plasminogen activator inhibitor type 1 (PAI-1) from platelets following their accidental activation in vitro during blood collection, we studied the antigen levels of PAI-1 and β-thromboglobulin (βTG) in plasma and sera from 38 healthy volunteers. For each volunteer, we calculated the ratio of platelet-derived PAI-1/ platelet-derived βTG from the difference in their respective concentrations in serum and plasma. The mean ± SD (0.012 ± 0.003) and median (0.012) ratios were identical before and after 10 or 20 min of venous occlusion. The platelet contribution of PAI-1 in plasma was estimated by multiplying the plasma concentration of βTG (as a marker of platelet activation) with the above-mentioned individual ratio. Under our conditions of blood collection (1/10 vol of 0.1 M citrate, pH 4.5, as anticoagulant, and handling of blood at 4 °C and within 30 min), the platelet contribution to the PAI-1 concentration in plasma was on average 12% and always negligible in plasma with high levels of PAI-1.
Increased Plasma Tissue-Type Plasminogen Activator Levels in Patients with Chronic Thrombocytopenia
Authors: Hanss M. , Ville D. , Dechavanne M.
Published: April 2009

Plasma fibrinolytic factors were measured in 14 patients with chronic idiopathic thrombocytopenic purpura (ITP), in 5 patients with chronic central thrombocytopenia and in 16 healthy volunteers. The von Willebrand factor (vWF), tissue-type plasminogen activator (t-PA) and D-dimer (DD) antigens were found to be significantly higher in both patient groups than in the control group. No difference appeared in euglobulin fibrinolytic activity and plasminogen activator inhibitor activity. The increases in both t-PA and vWF suggest the occurrence of an endothelial cell stimulation, associated with the reduction of circulating platelet number. The correlation of increased DD and t-PA levels during ITP can be the proof of a fibrinolysis activation and suggest an antifibrinolytic role of platelets at physiological concentrations. These results can justify antifibrinolytic therapy in bleeding thrombocytopenic patients.
Defibrotide Affects the Anticoagulant and Lipase-Releasing Activities of Heparin
Authors: Porta R. , Pescador R. , Mantovani M. , Prino G.
Published: April 2009

Defibrotide (DEF), an antithrombotic drug with no anticoagulant activity, given concomitantly with heparin potentiates its effects on thrombin time and lipase-releasing activity. Unlike heparin, DEF has hardly any lipase-releasing activity of its own. Most likely DEF interferes with pharmacokinetics of heparin. It is clear from the data reported here that when used in combination with DEF heparin should be administered at low doses and the coagulation parameters carefully followed.
Heparin and Thrombosis: A Seventy Year Long Story
Authors: Verstraete Marc
Published: April 2009

Heparin was a chance discovery made by a medical student who was searching for a clot-promoting activity in various tissue extracts and found an inhibitor of coagulation. It has taken 20 years from the discovery of heparin in 1916 to its therapeutic use (1937). This long delay was mainly due to problems with the purification and extraction on large scale of the active material. Standard unfractionated heparin is a mixture of mucopolysaccharide chains of various length that may range from 5,000 to 30,000 daltons. Heparin is only effective as an anticoagulant in the presence of a plasma protein, termed antithrombin III, with which it forms a complex. High- and low-affinity heparin are two types that readily bind or do not bind to antithrombin III. The pharmacokinetics of unfractionated heparin are compatible with a model based on the combination of a saturable and a linear mechanism. Low-molecular-weight heparins have been produced by a variety of techniques, and their molecular weights range from 3,000 to 9,000 daltons. These preparations have a ratio of anti-Xa activity to anti-II activity of approximately 4, while it is 1 for unfractionated heparin. After intravenous administration of low-molecular-weight heparins, the half-life of the antifactor Xa activity is considerably longer than for unfractionated heparin, while the anti-factor II half-lives are similar. In contrast to unfractionated heparin, low-molecular-weight heparin is virtually completely absorbed after subcutaneous administration, and its biological half-life is almost twice as long. In spite of certain differences with regard to the ratio between factor Xa and Ila inhibition, the various low-molecular-weight preparations show a rather similar absorption pattern. Low-molecular-weight heparins interact less with platelets than unfractionated heparin; nevertheless, a lower bleeding incidence with low-molecular-weight heparin for equivalent antithrombotic efficacy has yet to be established in man.
Heparin and Antiaggregating Therapy in Unstable Angina
Authors: Neri Semen G.G. , Modesti P.A. , Abbate R. , Gensini G.F.
Published: April 2009

Heparin and antiaggregating therapy represent an effective treatment of unstable angina. Aspirin is able to prevent myocardial infarction and death in patients with unstable angina, but is not able to control myocardial ischemia. On the contrary, heparin administered by continuous intravenous infusion (about 1,000 U/h) controls myocardial ischemia by very early lowering anginal attacks and silent ischemic episodes. Heparin intermittently administered (6,000 U i.v. four times daily) did not significantly affect anginal attacks and myocardial ischemia. Thrombolytic therapy alone (Alteplase 1.75 mg/kg) reduced, but not significantly, the number of anginal attacks. The reduction of myocardial ischemia induced by continuous infusion of heparin is associated with a decrease of fibrinopeptide A plasma levels, whereas the thromboxane B2 production by platelets seems to be irrelevant in order to obtain a reduction of myocardial ischemia. Thus thrombin formation seems to be a primary factor in the occurrence of refractory unstable angina and in the activation of platelets.
Low-Dose Heparin as an Antithrombotic Agent
Authors: Gensini G.F. , Bonechi F. , Gori A.M. , Fortini A. , Paniccia R. , Lamberti R. , Attanasio M. , Martini F. , Prisco D. , Neri Serneri G.G.
Published: April 2009

Heparin, after subcutaneous administration, has been found to be able to bind to endothelial receptors both in rabbits and in humans. N-sulphonate 35S-heparin remains bound in rabbits for at least 24 h and is able to enhance the inactivation process of thrombin and factor Xa. Heparin subcutaneously (200 U/kg) injected for 2 weeks resulted in an enhanced inactivation of thrombin and factor Xa by the endothelium. The antithrombin-enhancing activity persists longer than the anti-Xa activity. In man, daily subcutaneous administration of heparin (12,500 U/day) for 2 weeks significantly reduces the increased fibrinopeptide A plasma levels and normalizes the increased 125I-fibrinogen turnover. The present work indicates that heparin administration at a low dose represents a treatment able to remarkably enhance the antithrombotic properties of the vessel wall, independently of the presence of detectable heparin levels in the circulating blood.
Heparin and Secondary Prevention of Acute Myocardial Infarction
Authors: Lotto A. , Colombo A. , Talarico G. , Fratianni G. , Lettino M.
Published: April 2009

Patients surviving acute myocardial infarction (AMI) may experience several clinical events (reinfarction, congestive heart failure, sudden death) still responsible for high mortality rates. AMI early complicated by residual angina, left ventricular dysfunction, or malignant arrhythmias has a worse prognosis. Secondary prevention of myocardial infarction and death has been the end point of many clinical trials in the past two decades. It is well known that beta blockers prevent sudden death if administered chronically after AMI. Meta-analysis of controlled randomized trials demonstrated a significant reduction in reinfarction and vascular death with long-term antiplatelet treatment. Oral anticoagulants prevent fatal and non-fatal reinfarction and show a trend towards lower mortality rates, though treated patients have a higher incidence of haemorrhagic events, particularly stroke. Early administration of heparin gave contradictory results on short-term prevention of myocardial infarction and death after AMI. Data on long-term heparin therapy point out a significant reduction in recurrent AMI and a trend towards a decrease in general mortality.
Endothelial Cell Matrices Modulate Smooth Muscle Cell Growth, Contractile Phenotype and Sensitivity to Heparin
Authors: Herman Ira M.
Published: April 2009

Whereas vascular smooth muscle cell-extracellular matrix interactions have been intensively studied, our knowledge regarding the role that matrix plays in regulating the growth state and contractile phenotype of vessel wall cells is fragmentary. Of particular interest has been the demonstrable ability of (1) heparin to selectively inhibit vascular smooth muscle cell growth in vitro; (2) aortic endothelial cells to produce a heparin-like inhibitor of vascular smooth muscle cells, and (3) heparin to reverse smooth muscle cell proliferation in arteries that have been experimentally denuded of their endothelium. Recent work from our laboratory indicates that the endothelial cell synthesized extracellular matrix alters growth rate and heparin sensitivity of vascular smooth muscle cells. Whereas endothelial cell synthesized matrices that contain collagen and fibronectin promote smooth muscle cell growth, matrices containing heparan sulfate proteoglycan selectively inhibit identical smooth muscle cell populations. Similarly, these heparan sulfate enriched matrices lower smooth muscle sensitivity to heparin and positively influence the endothelial cells’ ability to produce the heparin-like inhibitor of vascular smooth muscle cell growth. In an effort to understand the mechanism mediating heparin’s effects on smooth muscle cell proliferation and contractile phenotype, we have analyzed the effects of heparin on vascular smooth muscle cell shape and actin isoform expression using doses of heparin previously shown to be growth inhibitory. The results of our studies indicate that heparin alters smooth muscle cell shape and cytoskeletal organization, suggesting that heparin’s growth inhibitory action may be related to its effects on cell shape. Additionally, the permissive effects that different endothelial matrices exert on vascular smooth muscle may selectively predispose specific subpopulations of arterial cells towards a proliferating phenotype, one associated with the genesis of atherosclerosis.
In vitro and ex vivo Activities of CY216: Comparison with Other Low Molecular Weight Heparins
Authors: Ofosu F.A.
Published: April 2009

Low molecular weight (LMW) heparins achieve their anticoagulant effects by inhibiting prothrombin activation, catalyzing endogenous thrombin inhibition, and binding thrombin. The extent to which each of the three actions of LMW heparins contributes to the antithrombotic effectiveness of LMW in man has not been defined. Several studies have reported that ex vivo anti-factor Xa activities of LMW heparins correlate with efficacy and potential haemorrhagic complications. However, critical review of the data suggests that anti-factor Xa assays are basically surrogate tests for the mass of LMW heparins in patients’ plasmas rather than reliable estimates of total catalytic concentrations of LMW heparins. Antithrombotic effectiveness of LMW heparins probably reflects their ability to inhibit coagulation in vivo. If the last concept proves correct, then results of tests which directly assess the extents to which LMW heparins have suppressed in vivo coagulation may provide more reliable markers for their antithrombotic effectiveness or lack thereof.
Therapeutic Application of Subcutaneous Low-Molecular-Weight Heparin in Acute Venous Thrombosis
Authors: Harenberg J. , Huck K. , Bratsch H. , Stehle G. , Dempfle CE. , Mall K. , Blauth M. , Usadel K.-H. , Heene D.L.
Published: April 2009

Fifty patients presenting with acute deep-vein thrombosis were randomized in a prospective, controlled study to determine the safety and efficacy of a treatment with low-molecular-weight (LMW) heparin compared with unfractionated heparin. LMW heparin (n = 24) was administered twice daily subcutaneously at a dose of 2 × 150 anti-Xa units/kg body weight, and unfractionated heparin (n = 26) was given intravenously by continuous infusion at a dose of 450 anti-Xa units/kg body weight daily for 10 days. Doses were adjusted to maintain peak anti-Xa levels between 0.5 and 1.0 anti-Xa units per milliliter. One patient in the unfractionated heparin group and 2 patients in the LMW heparin group suffered from bleeding complications. Two patients on LMW heparin and on unfractionated heparin had high evidence of pulmonary embolism based on defects on ventilation-perfusion scintigraphy. Control phlebography and duplex sonography demonstrated a significant improvement during both treatment regimens. Reperfusion of the deep-vein system was 70% with LMW heparin and 75 % with unfractionated heparin. The anti-Xa levels were significantly higher in the LMW heparin group, and activated partial thromboplastin and thrombin clotting times were significantly higher in the group receiving unfractionated heparin. Thrombin-anti-thrombin III complexes and D-dimer concentration decreased during the treatment, but did not differ between the two regimens. At the end of the treatment period with LMW heparin, protein C and antithrombin III were significantly higher.
Treatment of Deep Venous Thrombosis by Fixed Doses of a Low-Molecular-Weight Heparin (CY216)
Authors: Prandoni P. , Vigo M. , Cattelan A.M. , Ruol A.
Published: April 2009

Ninety consecutive outpatients with acute proximal and/or distal deep-vein thrombosis (DVT), as shown by phlebography, were entered into a prospective randomized trial comparing intravenous adjusted unfractionated heparin (UFH) with subcutaneous fixed doses of a low-molecular-weight heparin (CY216; 225 IC anti-Xa U/kg 12 hourly) for 10 days. The incidence of pulmonary embolism did not differ in the two groups (one episode per group). The comparison between pre- and posttreatment venograms and perfusion lung scans showed a statistically significant improvement (p < 0.01 and p < 0.05, respectively) only in the CY216-treated group. The incidence of major adverse reactions (major hemorrhages, relevant hemoglobin fall, and serious thrombocytopenia) was significantly higher (22 vs. 4.5%; p = 0.01) in the UFH-treated group. After a mean follow-up period of 2 years, the incidence of thromboembolic recurrences and that of post-thrombotic manifestations did not differ in the two groups. It is concluded that subcutaneous fixed doses of CY216 are more effective and safer than intravenous adjusted UFH in the treatment of acute DVT.
Failure of Recombinant Activated Factor VII during Surgery in a Hemophiliac with High-Titer Factor VIII Antibody
Authors: Gringeri A. , Santagostino E. , Mannucci P.M.
Published: April 2009

Recombinant activated factor VII (rFVIIa) was used before and after inguinal hernioplasty to prevent bleeding in a patient with hemophilia A complicated by a high-potency antifactor VIII inhibitor. rFVIIa (75 μg/kg) was given before and after surgery, first by bolus infusions at intervals of 2–3 h for 47 h and then by continuous intravenous infusion at a rate of 38 μg/h for an additional period of 12 h. Although no undue bleeding was observed during and for the first 26 h after surgery, the patient subsequently developed wound bleeding and hematomas that necessitated blood transfusion and infusion of porcine factor VIII. This case indicates that rFVIIa is not always successful in patients with antifactor VIII inhibitor and that more experience is needed to establish the optimal doses at surgery.
Substitution of Factor XIII: A Therapeutic Approach to Ulcerative Colitis
Authors: Lorenz R. , Heinmüller M. , Classen M. , Tornieporth N. , Gain T.
Published: April 2009

Three patients with ulcerative colitis in the active stage demonstrated reduced levels of F XIII activity and F XIII subunit A (61 and 80.3%, respectively). Because of the lack of clinical improvement during conservative therapy, the patients were treated additionally with F XIII concentrate (Fibrogammin HS®, Behring, FRG) for 10 days. The substitution resulted in an increase in F XIII activity (144.3%) and F XIII subunit A (238%) as well as in a marked improvement in symptoms.
Kinetic Analysis of the Clotting System in the Presence of Heparin and Depolymerized Heparin
Authors: Heuck Claus-Chr. , Baumann Peter
Published: April 2009

The kinetics of the activation of the plasmatic clotting system in the presence of heparin and depolymerized heparin (Kabi 2165), respectively, was compared with the kinetics of activation in plasma with isolated factor deficiency. Measurements were made with a chromogenic substrate method using Tos-Gly-Pro-Arg-p-nitroanilide acetate. The extinction curves were analyzed to determine the characteristics of a curve that was fitted to the experimental data to sufficiently describe the slope of the curves by constants. In the activated extrinsic clotting system, the action of heparin and depolymerized heparin results in a distribution pattern for the two relevant constants, K(l), defining the time of the point of inflection of the curve, and K(2), relating to the slope of the curve at the point of inflection, which is identical with the pattern observed in plasma with factor II deficiency. This distribution pattern can be explained by an inhibitory reaction on factor Ila, which is accelerated by the anticoagulant. In contrast, the pattern of K(2)/K(l) for the activated intrinsic system is identical with the pattern for plasma with factor X deficiency. Qualitative differences in the action of heparin and depolymerized heparin are not evident. The investigation confirms that the molecular action of heparin and depolymerized heparin as accelerators of the plasmatic clotting system is qualitatively the same. However, their action in the extrinsic and intrinsic system has different effects. Furthermore, the study reveals that constant K(2) is a more sensitive indicator to measure low heparin and depolymerized heparin activities than K(l) or its equivalent, the clotting time.
Haemorrhagic Effects of Unfractionated and Two Low Molecular Weight Heparins, Enoxaparin and Fragmin, in Rats
Authors: Bang Christen J. , Berstad Arnold , Talstad Ingebrigt
Published: April 2009

The effects on primary haemostasis of unfractionated heparin and of the two low molecular weight heparins, enoxaparin and fragmin, were compared in two rat models, one employing the gastric mucosa and the other the tail skin. All three heparin preparations prolonged the bleeding time and increased the blood loss dose dependently. The prolongation of the bleeding time per unit dose caused by unfractionated heparin was significantly greater than the prolongation caused by either one of the two low molecular weight heparins. In the gastric mucosa, but not in the tail skin, enoxaparin prolonged the bleeding time significantly less than fragmin (p < 0.05).