bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical and Therapeutic Aspects Associated to Phospholipid Binding Antibodies (Lupus Anticoagulant and Anticardiolipin Antibodies)
Authors: Ordi-Ros J. , Pérez-Pemán P. , Monasterio J.
Published: April 2009

Antiphospholipid antibodies (APA) comprise a family of immunoglobulins characterized by their pattern of reactivity in a number of laboratory tests. Included in this family are lupus anticoagulant (LA) anticardiolipin antibodies (ACA) and antibodies causing biologic false positive serologic tests for syphilis (BFP-STS). LA and ACA occur in a variety of conditions, including other autoimmunes disorders, infectious diseases, neoplasic disorders, in association with certain drugs and in otherwise healthy individuals. Clinical interest in LA and ACA is increasing. Antiphospholipid antibody syndrome is characterized by a triad of clinical features wich include fetal loss, thromboembolic disease and thrombocytopenia. Other clinical manifestations related with APA are livedo reticularis, cutaneous necrosis, hemolytic anemia, heart valve disease, chorea, migraina and obstetric problems as fetal growth retardation, pre-eclampsia, post-partum serositis or neonatal thrombosis or catastrophic antiphospholipid syndrome. Therapy is mainly directed against the widespread and diverse manifestations associated with the obstruction of small and large vessels. Long-term treatment with oral anticoagulation therapy is advised, even if the venous or arterial occlusion ocurred many years previously. In patients with primary antiphospholipid syndrome there is no evidence that the prophylactic administration of steroids or immunosuppression will prevent thromboembolic events. Although the administration of more energetic immunosuppression with cyclophosphamide in pulse form is effective in reducing elevated antibody levels, there is usually a rapid rebound to pretreatment levels shortly after discontinuation of the therapy. A history of recurrent fetal loss requires mandatory treatment during pregnancy. Although the actual prospective risk of pregnancy loss in women with antiphospholipid syndrome and prior pregnancy loss is unknown, it may exceed 60%. Because of this many investigators have treated women with antiphospholipid syndrome with either antiplatelet agents, immunosuppressive agents, or anticoagulants in an attempt to improve pregnancy outcome. Unfortunately, there is no unequivocal proof that any of these therapies are fully efficacious. Despite varying treatment protocols, the live birth rate with treatment was 70%, similar to that reported in the recent randomized clinical trial. Thrombocytopenia and autoimmune hemolytic anemia in patients with APA are treated similary as patients without APA. Treatment of asymptomatic patients isn’t indicated, because only approximately 10-15% of patients with APA developed complications.
Role of Plasminogen Activator Inhibitor Type 1 in the Pathogenesis of Coronary Artery Diseases
Authors: Aznar Justo , Estellés Amparo
Published: April 2009

Patients with ischaemic heart disease have high levels of plasminogen activator inhibitor type 1 (PAI-1). These levels can constitute an independent thrombotic risk factor. In addition, PAI-1 synthesis is greater in the atherosclerotic vessels than in the normal vessels and this can also constitute an atherogenic risk factor. There is a good correlation between insulinaemia and PAI-1, but it has not been demonstrated that the circulating level of PAI-1 depends exclusively on insulinaemia. The increased levels of PAI-1 correlate with other coronary risk factors, especially hypertriglyceridaemia, but high PAI-1 levels are also found in normolipaemic patients. Vascular synthesis of PAI-1 can be promoted by high levels of circulating lipoprotein a. Finally, an exercise programme can increase the fibrinolytic activity of heart disease patients towards normal.
Pathogenesis and Classification of von Willebrand Disease
Authors: Ruggeri Zaverio M.
Published: April 2009

Von Willebrand disease, the most common congenital bleeding disorder in humans, is the consequence of quantitative and/or qualitative defects of von Willebrand factor, a protein necessary for platelet adhesion and thrombus formation at sites of vascular injury. Distinct molecular defects of von Willebrand factor are responsible for the heterogeneity of von Willebrand disease subtypes. A classification in four main groups, each characterized by distinctive pathogenetic features, represents the basis for a correct therapeutic approach to bleeding episodes in these patients.
Response to 1-Deamino-8-D-Arginine Vasopressin in von Willebrand Disease
Authors: Lusher Jeanne M.
Published: April 2009

The synthetic agent, l-deamino-8-D-arginine vasopressin (DDAVP), is generally regarded to be the treatment of choice for persons with type I von Willebrand disease (vWD), and may be useful in type IIA vWD as well. Several formulations of the drug are available, including a highly concentrated intranasal spray formulation which is ideal for home use. The degree of F VIII and vWF response to DDAVP varies among individuals, but is generally consistent in individual patients over time. Some have tachyphylaxis while others do not. While side effects are uncommon, DDAVP is a potent antidiuretic agent. Thus one should be aware of the possibility of hyponatremia and water intoxication if certain precautions are not observed.
Biochemical Characteristics of Therapeutic Plasma Concentrates Used in the Treatment of von Willebrand Disease
Authors: Mannucci Pier Mannuccio
Published: April 2009

Therapeutic plasma concentrates containing von Willebrand factor (vWF) lack the largest, most hemostatically active multimers. In order to evaluate whether this abnormality results from proteolysis during manufacturing, we have analyzed the subunit structure of vWF in 21 commercial products and found a marked reduction in the relative content of intact 225 kD subunit, paralleled by an increase in the proteolytic fragments normally present in plasma, particularly that of 176 kD. There was no heightened vWF fragmentation in blood-bank cryoprecipitate prepared from platelet-poor, single-donor plasma; in contrast, there was a marked degree of fragmentation in cryoprecipitate prepared from pooled plasmapheresis plasma representing the starting fraction for the production of commercial concentrates. In cryoprecipitate prepared experimentally from plasma containing varying numbers of platelets, the degradation of vWF was proportional to the platelet count but was greatly diminished by adding protease inhibitors to plasma. On the basis of these findings, we postulate that the loss of the largest vWF multimers in commercial concentrates results from the use of poorly centrifuged plasmapheresis plasma containing an excessive number of residual platelets and leukocytes.
Experience with Haemate P in von Willebrand’s Disease in Adults
Authors: Scharrer I. , Vigh T. , Aygören-Pürsün E.
Published: April 2009

The virally inactivated pasteurized FVIII concentrate Haemate P contains nearly intact vWF multimers. It is currently the treatment of choice to achieve satisfactory hemostasis for moderate to severe vWD and for patients with variants of vWD that cannot be adequately treated with DDAVP or for whom DDAVP is contraindicated. Therefore, we treated patients with type la, type IIa, type IIb and type III vWD with Haemate P. A correction of the hemostatic defect was seen in all patients. The type of bleeding events included 24 gastrointestinal, 18 other mucosal, 5 central nervous system, 15 orthopedic and other. 28 dental surgical procedures, 9 operative deliveries, tonsillectomies, 17 orthopedic and 11 miscellaneous surgeries were performed under the cover of Haemate P.
Haemate P® in Children with von Willebrand’s Disease
Authors: Kreuz W. , Mentzer D. , Becker S. , Scharrer I. , Kornhuber B.
Published: April 2009

In our center, 289 children with von Willebrand’s disease (vWD) have been diagnosed since 1982. The majority of cases (n = 198) were congenital vWD whereas 91 patients suffered from vWD induced by valproate (VPA). We overview bleeding episodes in 45 children and 64 operative procedures requiring therapeutic intervention. The aim of therapeutic and prophylactic procedures in vWD is correcting the hemostatic disorder and normalization of bleeding time. This can be achieved by application of Haemate P leading to an elevation of plasma levels of von Willebrand parameters together with normalization of bleeding time. In patients with vWD type I, DDAVP will be preferred if contraindications can be excluded and efficacy has been shown. Severe bleeding complications could be prevented in a total of 50 surgical procedures in children with vWD type I by prophylactic treatment with DDAVP or Haemate P. Two children initially treated with DDAVP had to be substituted with Haemate P in the follow-up because of continuous bleeding. In type IIa and type III vWD as well as in VPA-induced vWD, the use of Haemate P was essential for sufficient hemostasis in all bleeding and operations. We conclude that Haemate P provides effective bleeding prophylaxis and treatment in all types of vWD except platelet-type.
Safety of Plasma Derivatives
Authors: Ingerslev J.
Published: April 2009

In clinical treatment practice of substitution therapy involving a plasma component, numerous aspects related to recipient’s safety are relevant to the physician. Since viral contaminants may be present in the donor blood, safety begins in the institution collecting raw plasma where donors are inquired about any unusual behavior that may potentially threaten safety. Other measures that could lead to exclusion of a donation are positive serological tests for HIV and hepatitis B and C. In this context, meticulously accurate logistics are mandatory. During the course of manufacture of plasma products, viral inactivation procedures have been adopted based on chemical and physical principles. The distinct effects of these depend on methodology and the types of virus in question. An important safety measure relates to establishing that the label value of content corresponds to the in vivo recovery of the reconstituted plasma derivative and, by inference, the clinical efficacy of the product. In patients deficient in plasma coagulation factors, treatment may trigger the development of functionally inhibiting alloantibodies against the factor needed for substitution which is a significant clinical complication. The reported incidences of such inhibitors have varied greatly. No clear relationship between their frequency and the type of concentrate used have been established. However, recent experience has shown an unexpected increase in inhibitors in a regional subset of previously stable patients when shifted from a dry-heat-inactivated concentrate to a pasteurized version of the same concentrate. Hence, the possible introduction of neoantigens is important. In the early era of concentrate use, side effects to treatment were often observed like alloimmune hemolytic anemia and various degrees of anaphylactoid reactions. With the appearance of concentrates of increased purity that contain less unwarranted proteins, side effects of this kind have been rare. In conclusion, safety of plasma derivatives by today’s standards is not a single entity, but a long chain of interdependent issues, each of which needs full attention to protect patients from mild and serious treatment complications.
The Quick Machine – A Mathematical Model for the Extrinsic Activation of Coagulation
Authors: Pohl B. , Beringer C. , Bomhard M. , Keller F.
Published: April 2009

The present paper describes a mathematical model of the kinetics of the extrinsic coagulation cascade in vitro. The coagulation factors FI, FII, FV, FVII, FX, heparin and antithrombin III (ATIII) as well as soluble fibrin polymers are considered. The effect of single-factor deficiencies of the factors II, V, VII and X, diseases like hypo- and dysfibrinogenaemia, hepatic insufficiency, inhibited polymerisation by degradation products, heparin therapy with and without ATIII deficiency and coumarin therapy on prothrombin time can be portrayed. Physiology of coagulation is represented in a dynamic mathematical model as a differential equation system. The model is based on three reaction types: enzymatic cleavage, complex formation and polymerisation. The model was implemented in a continuous simulation program on a personal computer using the Pascal programming language. Unknown rate constants were estimated by χ2 fit. Prothrombin time calculated by the model was compared to the training set of 20 plasma samples. In most but not all cases the model harmonized quite well with the coagulometric data.
Diagnostic Methods for Deep Vein Thrombosis
Authors: Wheeler Brownell , Anderson, Jr. Frederick A.
Published: April 2009

Clinical diagnosis of deep vein thrombosis (DVT) is unreliable, and treatment should not be undertaken without objective confirmation. The traditional ‘gold standard’ for the diagnosis of DVT has been venography, but ultrasonic imaging has now replaced venography as the new diagnostic standard in many hospitals. A variety of noninvasive physiologic tests are also useful in selected circumstances. These include plethysmography, Doppler flow studies, radioisotope tests, thermography and peripheral blood tests which reflect activation of coagulation or thrombolysis. We describe the clinical application of these diagnostic procedures, both for symptomatic patients suspected to have DVT and for asymptomatic patients at high risk for DVT. The selection of an appropriate diagnostic modality depends upon institutional capabilities, cost-effectiveness and individual patient circumstances.
Diagnosis of Deep Vein Thrombosis in Asymptomatic High-Risk Patients
Authors: Agnelli Giancarlo , Radicchia Stefano , Nenci Giuseppe G.
Published: April 2009

Postoperative deep vein thrombosis is usually asymptomatic so that pulmonary embolism is often the first clinical manifestation of venous thromboembolism. The diagnostic accuracy of impedance plethysmography, 125I-fibrinogen leg scanning and real-time B-mode ultrasonography has been extensively evaluated in patients with asymptomatic deep vein thrombosis. Impedance plethysmography has been evaluated in a number of studies and its sensitivity has been invariably found to be approximately 20% or less. These results seem to be due to the high prevalence in asymptomatic patients of distal, small and nonocclusive thrombi, unable to produce a critical obstruction of the venous flow. The accuracy of 125I-fibrinogen leg scanning has been assessed in a number of studies and found to be significantly different in the initial and more recent studies. This difference has been found to be due to the quality of the study design: the better the methodology, the lower the diagnostic accuracy of 125I-fibrinogen leg scanning. The association of impedance plethysmography and 125I-fibrinogen leg scanning do not result in an improvement of the results obtained by the single diagnostic method. Study methodology strongly influenced the results obtained with real-time B-mode ultrasonography with a reported sensitivity of approximately 50% in the studies performed adopting an appropriate methodology. In conclusion, noninvasive diagnostic methods are inaccurate in the diagnosis of asymptomatic deep vein thrombosis. Thus, venography remains the only accurate diagnostic method for the diagnosis of asymptomatic deep vein thrombosis.
Diagnosis of Recurrent Deep Vein Thrombosis
Authors: Koopman M.M.W. , Büller H.R. , ten Cate J.W.
Published: April 2009

After a first episode of deep vein thrombosis (DVT), 30-50% of the patients will develop complaints suspect of recurrent DVT. Of these patients, only 20-30% do indeed have a recurrent episode of DVT. To identify patients with a true recurrent DVT, objective testing is mandatory in every patients. However, all the available tests have their limitations in patients with recurrent DVT. In this review, diagnostic strategies using venography, impedance plethysmography, 125I-fibrinogen leg scanning and ultrasonography in patients with recurrent DVT will be discussed. Furthermore, some epidemiologic data and pathophysiologic mechanisms concerning DVT will be considered.
Diagnostic Problems with Venous Thromboembolic Disease in Pregnancy
Authors: Douketis J.D. , Ginsberg J.S.
Published: April 2009

In the pregnant patient with suspected deep vein thrombosis (DVT) or pulmonary embolism (PE), accurate diagnosis is required to identify patients with DVT or PE who would benefit from appropriate anticoagulant therapy, and to exclude DVT and PE in the majority of patients so they are not exposed to the risks of anticoagulants. The diagnosis of DVT and PE during pregnancy is problematic. The use of invasive diagnostic tests, such as venography and pulmonary angiography, is limited because of the potential risks to the fetus of radiation exposure. Due to hemodynamic changes associated with pregnancy, noninvasive diagnostic tests such as impedance plethysmography and venous Doppler may be falsely abnormal. Diagnostic approaches for DVT and PE will be outlined that can accurately and safely confirm or exclude suspected DVT and PE during pregnancy.
The Diagnosis of Pulmonary Embolism
Authors: Kearon Clive , Hirsh Jack
Published: April 2009

Although clinical diagnosis of pulmonary embolism (PE) is not sufficiently reliable to determine management, it is valuable for stratifying patients into high, intermediate, and low clinical suspicion of embolism. Clinical assessment can then be combined with lung scanning to identify groups of patients with a sufficiently high or low probability of PE that a decision to anticoagulate or withhold therapy can be made. Approximately half of patients with suspected PE will fall into one of these categories. Thrombosis in the deep veins of the leg (DVT) can be detected by noninvasive tests in approximately 50%, and by bilateral venography in approximately 70% of patients with PE, and provides grounds for anticoagulation of some patients with nondiagnostic combinations of clinical and lung scan assessments. Failure to detect DVT makes it less likely but does not exclude the possibility that the patient had a PE. Preliminary evidence suggests that the majority of patients with nondiagnostic combinations of clinical assessment, lung scanning, and negative noninvasive tests for DVT can safely be managed without anticoagulation, provided serial noninvasive tests for DVT remain normal over a 2-week period. Pulmonary angiography may be advisable in patients with nondiagnostic combinations of the above tests in whom (a) the probability of PE remains high (e.g. 30-80%), (b) cardiopulmonary reserve is poor, (c) serial follow-up is not feasible, or (d) future management (e.g. subsequent pregnancy) would be influenced by the result. D-Dimer measurements are sensitive but nonspecific for PE and therefore may have a high negative predictive value, further simplifying the diagnostic approach to PE.
Factor VIIShinjo: A Dysfunctional Factor VII Variant Homozygous for the Substitution Gln for Arg at Position 79
Authors: Takamiya O. , Abe S. , Yoshioka A. , Nakajima K. , McVey J.H. , Tuddenham E.G.D.
Published: April 2009

We report a factor VII (FVII) variant, FVIIShinjo, characterized by normal FVII antigen levels and variable procoagulant activity using tissue thromboplastin from different sources. Normal FVII activity is obtained using human placenta thromboplastin but low activity using rabbit or bovine brain thromboplastin. Exons 2-8 and the intron-exon junctions of the FVII genes of the propositus were amplified by PCR from DNA extracted from peripheral white blood cells, and screened by single-strand conformational polymorphism (SSCP) analysis. DNA fragments showing aberrant mobility were cloned and sequenced. We detected a single-point mutation, a homozygous G to A transition at nucleotide position 6,055 in exon 4, which results in the substitution of Arg 79 by Gln in the first EGF-like domain. This mutation results in a loss of a site for the restriction endonuclease Msp I. The Msp I digestion pattern of the PCR-amplified exon 3+4 fragments from each member of the family was determined. The Msp I haplotypes were consistent with this G to A transition being associated with reduced FVII activity as detected using thromboplastins from various species. We conclude that the Arg 79 to Gln substitution in the first EGF-like domain of FVII identified in the propositus is responsible for the inherited FVII abnormality in this Japanese family. We postulate that one of the sites of interaction between FVII and tissue thromboplastin includes Arg 79 in the first EGF-like domain of factor VII.
Sensitivity of Sixteen APTT Reagents for the Presence of Lupus Anticoagulants
Authors: Denis-Magdelaine A. , Flahault A. , Verdy E.
Published: April 2009

Activated partial thromboplastin time (APTT) is the most common assay used to screen for lupus anticoagulant (LA). For some years, manufacturers have been proposing APTT reagents that were more sensitive to LA. In this study, we evaluated the sensitivity and responsiveness of 16 APTT reagents in 40 LA and 46 normal plasmas. Sensitivity was established using a 1:1 mixture of normal and LA plasma that optimized the most sensitive reagent. The same pool of normal plasma was used for the assay of mixtures and daily APTT values for the determination of ratios. The results show that new commercially available APTT reagents are more sensitive and responsive to LA. The different sensitivities of APTT reagents might be partly due to the heterogeneity of LAs and several APTT reagents should be used for LA detection. The choice of APTT reagents constitutes an important preliminary step for LA evaluation.
Circadian Variations of Plasminogen Activator Activity, Tissue-Type Plasminogen Activator Antigen, Plasminogen Activator Inhibition and Plasmin Inhibition in Rat Aorta, Heart and Brain Are Influenced by Endotoxin or Aspirin or Endotoxin plus Aspirin
Authors: Kokolis N. , Rekkas C. , Tsandarliotou M. , Smokovitis A.
Published: April 2009

The effect of aspirin or endotoxin or aspirin plus endotoxin on the circadian variations of plasminogen activator activity (PAA), tissue-type plasminogen activator (t-PA) antigen level, plasminogen activator inhibition (PAI) and plasmin inhibition (PI) in aorta, heart and brain of the rat was studied. In aorta the circadian variations of PAA, t-PA antigen and tissue-type PAI (t-PAI) were blunted by endotoxin, while the circadian variation of PI was reversed; t-PAI variation was blunted by aspirin plus endotoxin, while PI variation was reversed. Various disturbances of the circadian variations of PAA, t-PA antigen, PAI or PI in heart and brain were also observed. In conclusion, the circadian variations of fibrinolytic parameters in key organs are influenced by aspirin or endotoxin or aspirin plus endotoxin in a varying way or degree depending on the treatment, the parameter studied or the organ.
Comparison of a New Automated Kinetically Determined Fibrinogen Assay with the 3 Most Used Fibrinogen Assays (Functional, Derived and Nephelometric) in Austrian Laboratories in Several Clinical Populations and Healthy Controls
Authors: Halbmayer Walter-Michael , Haushofer Alexander , Schön Renate , Radek Johannes , Fischer Michael
Published: April 2009

A new automated kinetically determined fibrinogen assay was measured in plasmas of healthy subjects and three clinical cohorts (acute-phase reaction, liver cirrhosis and fibrinolytic therapy) that were expected to show normal, high and low levels of fibrinogen. The results were compared with the results of fibrinogen measurement using the derived method, the method according to Clauss and an immunological-nephelometric method. Altogether, the best correlation was achieved between the kinetic and the derived method. However, results from the derived method were generally higher than values obtained through the kinetic method. This was particularly true for high concentration levels above 400 mg/dl (patients with acute phase reaction) as well as for plasmas containing fibrin(ogen) degradation products and low concentrations of fibrinogen (below 150 mg/dl). Fibrinogen determinations in several commercial plasma pools with declared fibrinogen levels show remarkable heterogeneity when different methods were applied. To improve the discernment of fibrinogen determinations we suggest adjustment of standard preparations to international reference materials and the specification of the method used. Furthermore the attending physician is asked to cast a critical eye on fibrinogen values with regard to the used method of determination.
Prevention of Experimental Venous Thrombosis in Rabbits with Different Low Molecular Weight Heparins, Dermatan Sulphate and Hirudin
Authors: Matthiasson Stefan E. , Lindblad Bengt , Bergqvist David
Published: April 2009

In a randomized, blind study the antithrombotic efficacy of dermatan sulphate (DS), recombinant hirudin (r-hirudin) and four commercially available low molecular weight heparins (LMWHs) was investigated after intravenous administration in a jugular vein thrombus model in rabbits utilizing a combination of endothelial damage and flow reduction. The parameters observed were the frequency of visible thrombosis, the frequency of occlusive thrombosis and thrombus weights. DS and r-hirudin were investigated in one fixed dose and the LMWHs in prophylactic doses, adjusted to body weight, recommended in high-risk situations by the manufacturers. All substances effectively reduced the three observed parameters. DS and r-hirudin were equally or even more effective than the LMWHs. Although significant differences were not found between the individual LMWH treatments a visible trend cannot be overlooked in all three observed parameters. This cannot solely be explained by the different antifactor Xa activity doses given but increased antithrombotic activity was observed with declining antifactor Xa/antifactor Ila ratio. Our findings indicate that the different commercial LMWHs may differ in their antithrombotic activity when given in recommended doses adjusted to body weight in this experimental model. Dose range studies are required to clarify the thrombo-prophylactic efficacy of DS and r-hirudin in relation to the tested LMWHs.
Increased Cerebral Perfusion following Reduction of Fibrinogen and Lipid Fractions
Authors: Walzl B. , Walzl M. , Valetitsch H. , Lechner H.
Published: April 2009

High levels of plasma fibrinogen in cerebrovascular disease cause deterioration in the hemorheologic pattern, microcirculation and cerebral perfusion. We compared the value of hepa-rin-induced extracorporeal LDL precipitation (HELP) which is a method that safely and effectively reduces plasma fibrinogen and lipoproteins and so improves the hemorheologic pattern and blood flow properties. Regional cerebral blood flow (rCBF) was measured by the 133Xe SPECT clearance method. After first measuring rCBF, 15 patients suffering from cerebral multi-infarct disease underwent a single HELP application. One hour later a second measurement of rCBF was performed. Fifteen other patients with similar clinical symptoms and findings on CAT scans who were not subjected to HELP served as controls. The HELP treatment produced an immediate and statistically significant reduction of all parameters relevant to hemorheology, such as plasma fibrinogen, whole blood viscosity at both high and low shear rate, plasma viscosity, and red cell transit time. Total cholesterol, low density lipo-protein, and triglycerides were also reduced. The treated group showed 9.7-19.9% increased rCBF in different vascular regions examined relative to the untreated controls. The results obtained indicate that HELP has a potent effect in a situation demanding rapid and significant improvement of the blood flow.
Modifications of Platelet Shape Change and ATP Release during Cardiopulmonary Bypass
Authors: Jung G. , Razafindranaibe F. , Elkouby A. , Durasnel P. , Panes F. , Monassier J.-P.
Published: April 2009

Platelet activation is accompanied by characteristic morphological changes: smooth-disc platelets become more spherical in shape and develop pseudopods. The purpose of this study is to investigate whether platelets change after extracorporeal bypass. Twenty-two patients undergoing cardiopulmonary bypass (CPB) were studied prior to anesthesia and immediately after the operation. Platelets activated by different agonists were monitored simultaneously for morphological changes, ATP release and aggregation. While shape change measured before surgery was large, it was significantly reduced after bypass surgery (p < 0.01); morphological changes were quicker postoperatively. Several other parameters also changed: the time lapse between administration of the agonist and the start of ATP secretion decrease significantly (p < 0.01). After activation with high concentrations of ADP, ATP release was significantly increased (p < 0.01). On the other hand, less ATP was released after platelet activation with collagen and arachidonic acid, suggesting a change in platelet adhesion or a downregulation of endoperoxide synthesis. In our study, the importance of preactivation change in shape, estimated quantitatively by percent loss in ability of changing shape, can be compared using various agonists, with proportional defects in release and aggregation. These data provide evidence for different intrinsic levels in platelet defects after CPB.
Effects of Ditazol on the Vascular Retinal Pattern in Experimental Diabetes in Rats
Authors: Moreno A. , De La Cruz J.P. , Mérida F. , García Campos J. , Sánchez de la Cuesta F.
Published: April 2009

Platelets from diabetic patients are hypersensitive to aggregating agents. An imbalance in thromboxane/prostacyclin synthesis has been postulated as an antecedent to the development of diabetic retinopathy. We studied 3-month streptozotocin-diabetic rats (SDR) treated with 200 mg/kg/day p.o. of ditazol, an antiplatelet drug that inhibits thromboxane formation. Thromboxane B2 (TxB2) production was higher and 6-keto-PGF1α synthesis lower in SDR than nondiabetic rats (NDR). In treated animals, ditazol inhibited platelet aggregation by 66%, and TxB2 production by 58%, and increased vascular 6-keto-PGF1α by 45%. Furthermore, 13% of the retinal surface was covered by peroxidase-labelled vessels in NDR, 2.1% in nontreated SDR, and 8.9% in SDR treated with ditazol. We postulate that ditazol may prevent or reduce diabetic retinopathy.
Effects of Ionic and Nonionic Contrast Media on Clot Structure, Platelet Function and Thrombolysis Mediated by Tissue Plasminogen Activator in Plasma Clots
Authors: Carr, Jr. Marcus E. , Carr Sheryl L. , Merten Suzan R.
Published: April 2009

Various radiographic contrast agents have anticoagulant or prothrombotic properties. Ionic agents are reported to have greater antithrombotic potential while nonionic agents are considered more thrombogenic. Some agents alter fibrin structure and bind to platelets in purified systems. This study compared the effects of iohexol, a nonionic agent, and iothalamate, an ionic agent, on fibrin assembly, clot structure, platelet function and clot dissolution in plasma. Plasma gels containing increasing concentrations of iothalamate were composed of thinner fibers with decreased fiber mass/ length ratios (μ) and reduced gel turbidity. Such clots were more rigid and more resistant to fibrinolysis induced by tissue plasminogen activator (tPA). Gel elastic modula increased from 10,000 to 27,000 dyn/cm2 as iothalamate concentration increased from 0 to 20 mM. 50% lysis time increased from 800 to 1,250 s with the addition of 10 mM iothalamate. At 20 mM, iothalamate had no effect on ADP-induced platelet aggregation but prolonged the lag phase seen with collagen-induced aggregation. Platelet force development increased from 15,300 to 20,400 dyn with 20 mM iothalamate. The effects of iohexol were similar. Gel optical density dropped from 0.50 to 0.32, μ fell from 3.3 to 2.2 × 1013 D/cm, and elastic modulus rose from 11,000 to 24,000 dyn/cm2 as iohexol concentration was increased from 0 to 20 mM. Clots formed in the presence of 60 mM iohexol and tPA did not dissolve in 72 h while control clot 50% lysis time was 450 s. At concentrations ≥ 40 mM, iohexol completely blocked collagen-induced platelet aggregation. Platelet force development increased from 7,660 to 19,600 with 40 mM iohexol. Contrast media possess profound fibrin-altering activities in plasma. Fibrin formed in the presence of some agents may be significantly more resistant to fibrinolysis.
In vitro Characterization of Antithrombin III Concentrates – A Single-Blind Study
Authors: Hellstern Peter , Moberg Ulla , Ekblad Monica , Anders Christian Ulrich , Faller Beate , Müller Sabine
Published: April 2009

Twenty-three lots of five antithrombin III (AT III) concentrates from four manufacturers were analyzed in a single-blind study. All the preparations had been virus-inactivated by pasteurization, and one concentrate had also been treated with solvent/detergent (S/D). AT III activities were determined using two thrombin-based and one factor Xa-based chromo-genic substrate assays. AT III antigen was measured by kinetic nephelometry. All AT III assays were tested against the first international reference preparation coded 72/1. In addition, AT III was characterized by crossed immunoelectrophoresis in the presence of heparin and by gel filtration. The following were quantified: heparin cofactor II activity and antigen content, heparin activity, thrombin-AT III complexes, AT III-protease complexes, total protein, albumin, immunoglobulins, glucose and pH. The AT III concentrates differed markedly in terms of their purity and potency. The specific activities of AT III and the ratios of AT III activity to antigen content ranged from 3.4 to 6.9 and from 0.63 to 0.84, respectively. The highest values were found in five lots of the concentrate that had been treated by both pasteurization and S/D. This preparation was the only one that was virtually free of denaturated AT III, as judged by crossed immunoelectrophoresis. Marked batch-to-batch variation in AT III potencies was found in two out of the five preparations analyzed. In two out of five lots from one manufacturer, the measured potencies were more than 10% lower than the declared potencies. None of the analyzed preparations contained heparin cofactor II, and heparin activities were very low in all lots.
Efficacy and Safety of a Monoclonal Purified Factor VIII Concentrate: 5-Year Follow-Up in Previously Treated HIV-Negative Haemophiliacs
Authors: Smid W.M. , van der Meer J. , Halie M.R.
Published: April 2009

The efficacy and safety of a monoclonal purified factor VIII concentrate (Hemofil M) were assessed in a historically controlled study in 22 HIV-negative patients with haemophilia A, previously treated with various concentrates. Data from 5 years of follow-up were compared with those from the preceding 6 months. Factor VIII consumption remained unchanged. A temporary increase in the number of reported bleedings was attributed to more frequent follow-up visits in the first year. Allergic reactions, inhibitor formation and HIV infection were not seen. Liver function parameters fluctuated in individual patients, and were not related to the ultrapure concentrate used. No clinical evidence of liver insufficiency was seen. The number of CD4-positive lymphocytes was stable, while platelet numbers showed a remarkable increase. We conclude that in previously treated HIV-negative haemophiliacs, treatment with a monoclonal purified factor VIII concentrate is efficacious and safe with regard to HIV transmission, allergic reactions, induction of inhibitors, and deterioration of immune abnormalities.
Effects of Desmopressin on Hemostasis in Patients with Liver Cirrhosis
Authors: Agnelli Giancarlo , Parise Pasquale , Levi Marcel , Cosmi Benilde , Nenci Giuseppe G.
Published: April 2009

The aim of this double-blind, placebo-controlled crossover study was to investigate the effect of 1-deamino-8-D-arginine vasopressin (dDAVP) on hemostasis in patients with chronic liver disease. Nine consecutive patients with biopsy-proven liver cirrhosis and related coagulation abnormalities received in a random order dDAVP, 0.5 μg/kg, or saline intravenously. Blood samples were taken before dDAVP infusion and 30, 60 and 180 min after its end. dDAVP infusion induced a statistically significant shortening of the bleeding time from 9 min (range 6.5-15.5) to 6 min (range 4.5-9.5) at 1 h after the infusion. The activated partial thromboplastin time was significantly shortened at 30 and 60 min after dDAVP infusion. Plasma levels of factor VIII, XI and XII coagulant activities were significantly increased at all sampling times after dDAVP infusion. The maximum increase over basal values in plasma levels of factor VIII, XI and XII was 63, 22 and 40%, respectively. dDAVP did not induce any significant changes of prothrombin time, thrombin clotting time, fibrinogen, plasma levels of factor II, V, VII, IX, X, factor XII antigen, protein C (activity and antigen), antithrombin III, plasminogen and α2-antiplasmin. Placebo infusion did not produce any significant changes in the evaluated parameters. We conclude that dDAVP can positively influence the hemostatic system in patients with liver cirrhosis. The clinical relevance of this hemostatic improvement deserves further evaluation.
Plasminogen Activators and Plasminogen Activator Inhibitor before and after Surgery in Patients with and without Gastric Malignancy
Authors: Rahr Hans B. , Sørensen Jens V. , Larsen Jens F. , Jensen Frank Svendsen , Bredahl Claus
Published: April 2009

Pre- and postoperative plasma levels of tissue-type plasminogen activator (t-PA), single-chain urinary plasminogen activator, and plasminogen activator inhibitor 1 (PAI-1) were measured in 40 patients undergoing gastric surgery in order to compare patients operated for benign (n = 21) and malignant (n = 19) disease. On the 1st postoperative day, the PAI-1 activity was significantly increased and the t-PA activity significantly decreased in the malignant group, whereas only insignificant changes were seen in the benign group. In contrast, the t-PA activity was significantly increased 1 week after surgery in patients without malignancy. In both groups, the single-chain urinary plasminogen activator activity decreased on the 1 st postoperative day, but was significantly increased 1 month after operation. Thus, the two groups reacted differently, but it remains to be determined whether this bears any relationship to the well-known high risk of postoperative venous thrombo-embolism in cancer patients.
The Fibrinolytic Activity of Staphylokinase Mutants in the Fibrin Plate Assay
Authors: Hauptmann J. , Gührs K.-H. , Hartmann M. , Schlott B.
Published: April 2009

The fibrinolytic activity of the new plasminogen activator, recombinant staphylokinase, was compared to that of streptokinase and tissue-type plasminogen activator in the fibrin plate assay. The pattern of fibrinolysis by staphylokinase on fibrin plates differs from the other plasminogen activators. A number of mutants of staphylokinase with various amino acids in position 26 substituted for methionine in wild-type staphylokinase were compared with respect to their fibrinolytic potencies. Only the mutants with cysteine or leucine in this position have a fibrinolytic activity comparable to wild-type staphylokinase. The results on the fibrinolytic activities in the fibrin plate assay correlate with those of a plasmin generation assay, the latter is, however, less sensitive.
Close Relationships between Serotonergic and Fibrinolytic Systems Revealed by a Monoamine Oxidase Inhibitor Treatment in Rats
Authors: Urano Tetsumei , Malyszko Jolanta , Takada Yumiko , Takada Akikazu
Published: April 2009

In order to investigate a possible relationship between serotonergic and fibrinolytic systems, serotonin (5-hydroxytryptamine, 5-HT) metabolism was modified by the use of a monoamine oxidase inhibitor (tranylcypromine: 10 mg/kg body weight) and its effect on the fibrinolytic system was analyzed. Tranylcypromine caused a rise in whole blood 5-HT with a simultaneous fall in 5-hydroxyindoleacetic acid. Euglobulin clot lysis time was significantly prolonged 1 and 4 h after injection and tissue plasminogen activator (tPA) activity declined 4 h following administration with a simultaneous increase in its inhibitor (PAI) activity. Blood 5-HT was negatively related to tPA (r = -0.48; p < 0.05) and positively to PAI activities (r = 0.43; p < 0.05) in tranylcypromino-treated rats, whereas there were no such correlations in solvent-treated rats.
Effects of Long-Term Therapy with either Heparin or Low-Molecular-Weight Heparin on Serum Lipid Levels
Authors: Monreal M. , Lafoz E. , Urrutia A. , Roncales J. , Galimany R. , Biosca C. , Corominas A.
Published: April 2009

Beside the anticoagulant and antithrombotic activity, heparin also exerts a lipolytic activity. In a prospective study on patients with venous thromboembolism and some contraindications to coumarin therapy, a low-molecular-weight heparin (Fragmin®) was compared to unfractioned (UF) heparin in terms of both efficacy and safety. A secondary aim was to study the influence of both types of heparin on serum lipid levels. Sixty-six consecutive patients who were not taking concomitant treatment with lipid-lowering drugs entered the study. Patients received treatment with either UF heparin, 10,000 IU s.c, b.d., or Fragmin 5,000 IU anti-factor Xa s.c, b.d. for a period of 3 or 6 months, according to whether the initial diagnosis was deep venous thrombosis or pulmonary embolism. Each patient was followed up at 6-weekly intervals, and blood samples were obtained at discharge, and then 6 and 12 weeks after discharge. Finally, a further sample was obtained 3 months after therapy was discontinued. Total cholesterol levels increased significantly in both groups of patients: levels increased from 193 ± 56 to 246 ± 63 mg/dl in the UF heparin group (p < 0.001), and from 189 ± 53 to 222 ± 47 mg/dl in the Fragmin group (p < 0.05). The increase was mostly due to a very strong increase in HDL cholesterol levels in patients receiving UF heparin (from 46 ± 12 to 71 ± 23 mg/dl; p < 0.000005). Three months after discharge, HDL cholesterol levels were significantly higher in patients taking UF heparin than in patients in Fragmin (p = 0.006). By contrast, patients on Fragmin exhibited a significant increase in LDL cholesterol levels: from 112 ± 39 to 139 ± 37 mg/dl; p < 0.01.
Does Glycosylation Influence the Experimental Antithrombotic Effect of a Two-Domain Tissue Factor Pathway Inhibitor?
Authors: Holst Jan , Lindblad Bengt , Nordfang Ole , Østergaard Per B. , Hedner Ulla
Published: April 2009

We have earlier shown that both full-length and truncated glycosylated tissue factor pathway inhibitor (TFPI) lacking the third Kunitz domain and the c-terminal region has an antithrombotic effect comparable to low-molecular-weight heparin (LMWH) in an experimental venous thrombosis model. The aim of this study was to investigate whether a recombinant truncated non-glycosylated TFPI (117QTFPI1-161) had an antithrombotic effect similar to the glycosylated TFPI1-161 and LMWH. We also followed the coagulation parameters. The thrombi were induced in rabbit jugular veins with a combination of endothelium destruction and restricted blood flow. Group 1: placebo; group 2: LMWH 60 anti-Xa IU/kg, i.v.; groups 3 and 4: TFPI1-161 0.8 and 0.2 mg/kg, i.v., respectively; groups 5 and 6: 0.8 and 0.2 mg/kg 117QTFPI1-161, i.v., respectively, in a randomized double-dummy fashion. Twelve animals were included in the placebo group and 6 in each of the other groups. The frequency of thrombosis and also of occlusive thrombosis was reduced in all groups compared to placebo. The thrombus weight was reduced (0-9.9 mg) in all groups, significantly in groups 2, 4 and 5 (p = 0.004-0.02) compared to placebo (21.1 mg). In group 3, a borderline p value was achieved (0.06 likely a β-error). The two forms of TFPI1-161 given in the higher doses showed a significantly greater increase of anti-Xa activity, but with a shorter duration compared to LMWH (1.7-1.9 vs. 0.9 anti-Xa IU/ml). Activated partial thromboplastin time (aPTT)-analysis revealed that only LMWH (52 s) caused a significant transient elevation 2 min after injection. In the other groups, a temporary but insignificant elevation of aPTT (27-37 s) was seen. No detectable effect on anti-Xa activity and prothrombin time (PT) was seen in any TFPI group. The glycosylation of the second domain on TFPI does not substantially contribute to the antithrombotic effect of TFPI. Regardless of the glycosylation of TFPl1-161, it has a dose-dependent effect on anti-Xa, a small effect on the aPTT, but no effect on anti-Xa and PT. LMWH has a more pronounced and sustained impact on these parameters.
Participation of αIIbβ3 in Platelet Microparticle Generation by Collagen plus Thrombin
Authors: Nomura Shosaku , Komiyama Yutaka , Matsuura Eiji , Xie Gui Lan , Katsura Kaoruko , Miyake Tetsuya , Miyazaki Yasuhiko , Kagawa Hideo , Koike Takao , Fukuhara Shirou
Published: April 2009

We investigated the role of αIIbβ3 in microparticle generation by normal and thrombasthenic platelets stimulated with collagen plus thrombin. Microparticle generation by normal platelets was scarcely inhibited by monoclonal antibodies for glyco-protein lb and glycoprotein IX. Although one monoclonal anti-α αIIbβ3 antibody (NNKY1-32) partly inhibited microparticle generation, 3 other monoclonal anti-α αIIbβ3 antibodies had little effect. However, the combination of 4 monoclonal anti- αIIbβ3 antibodies or treatment with a polyclonal anti- αIIbβ3 antibody significantly inhibited microparticle generation (p < 0.05). Microparticle generation by thrombasthenic platelets also occurred after stimulation with collagen plus thrombin, although at a significantly lower level compared with normal platelets. Monoclonal antibodies for resting αIIbβ3, P-selectin, activated αIIbβ3 and β2-glycoprotein I bound to microparticles from healthy platelets. In contrast, only a monoclonal antibody for β2-glycoprotein I bound to thrombasthenic microparticles. These results suggest that microparticle generation by collagen plus thrombin occurs via two different mechanisms which are dependent and independent of αIIbβ3, respectively. The αIIbβ3-dependent mechanism appears to require activation of αIIbβ3·
Plasma Serotonin and Platelet Aggregation during Ischemia-Reperfusion in Dogs: Effect of Dipyridamole and Coenzyme Q10
Authors: Choudhury Niaz Ahmed , Malyszko Jolanta , Ahmed Motahar Hossain , Pietraszek Michal Henryk , Nakamura Satoshi , Nakai Katsuhiko , Rashid Mohammad Abdur , Takada Akikazu , Baba Shozo
Published: April 2009

Platelet aggregation and plasma serotonin were studied during ischemia-reperfusion of the small intestine in dogs. Blood was withdrawn from the superior mesenteric vein before and 1 h after ischemia, then 5, 30 and 60 min after reperfusion. Dipyridamole (5 mg/kg body weight) and coenzyme Q10 (CoQ10; 10mg/kg body weight) were administered intravenously 5 min before reperfusion, following 1 h ischemia, in order to investigate their effects on platelet function and free serotonin. Ischemia-reperfusion resulted in an increased local free serotonin concentration together with an enhanced platelet response to ADP, collagen and arachidonic acid. Administration of dipyridamole and CoQ10 prior to reperfusion prevented, at least in part, augmented platelet activation and serotonin release. It appeared that dipyridamole was more potent than CoQ10. Our results may indicate a possible protective effect of dipyridamole on enhanced platelet activation during ischemia-reperfusion in dogs.