bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spontaneous Platelet Aggregation in Cerebrovascular Disease II
Authors: Hoogenduk E M G , Jenkins C S P , van Wijk E M , Vos J , ten Cate J W 
Published: July 2018

SummaryA group of 186 patients with Transient Ischaemic Attacks (TIA) or cerebral Infarction (Cl) was found to demonstrate in vitro Spontaneous Platelet Aggregation (SPA) in 39% of those studied. Of the 176 normal subjects studied the incidence of in vitro SPA was found to be 5%. Further investigation of the phenomenon of SPA revealed that:1. it is associated with ADP-hyperaggregability, i. e. the threshold concentration to induce second wave aggregation is decreased;2. it is dependant on the increase in pH which occurs in platelet-rich plasma stirring in an aggregometer while concurrent ADP-hyperaggregability is independant of this change in pH;3. it is associated with malondialdehyde production and the release of endogenous 5- hydroxytryptamine; and that4. in addition Km and Vmax values for [14C]-5HT incorporation are normal; and that5. no gross abnormalities of the platelet membrane glycoproteins were apparent although occasionally glycoprotein III was found to be increased.This study demonstrates abnormal platelet behaviour in patients with TIA and Cl where the enzyme system involved in thromboxane production is sufficiently stimulated, by stirring alone, to induce aggregation of platelets and the release reaction.Acetylsalicylic acid abolishes SPA and prolongs the bleeding time with similar characteristics as has been described for normal individuals. Plasma (3-thromboglobulin levels are significantly increased in the patients studied. However, no correlation was established with the incidence of in vitro SPA.
Fibrinogen Zurich I: Impaired Release of Fibrinopeptide A
Authors: Hofmann V , Gati W P , Straub P W 
Published: July 2018

SummaryFibrinogen Zurich I is characterized by an abnormal fibrin monomer polymerization. It consists of two fractions of molecules, one with a normal aggregation and one not aggregating at all and interfering with the aggregation of the normal population. Using a radioimmunoassay for fibrinopeptide A, only approximately half of the expected fibrinopeptide A could be recovered after thrombin or Defibrase proteolysis. The defective fibrinopeptide A release could be confirmed by measurement of the N-terminal Gly/Tyr ratio. It is likely that the abnormal fibrin monomer aggregation of the abnormal fraction of fibrinogen Zurich I is due to the defective fibrinopeptide A release of this fraction.
Liquoid Induced Stasis and the Generalized Shwartzman Reaction
Authors: Nordstoga Knut 
Published: July 2018

SummaryThe composition of the occlusive material within dilated glomerular capillaries, following intravenous injections of Liquoid in blue foxes, was studied electron microscopically; it was found that it mainly consisted of a debris in which disintegrated red cells constituted the major component. Damaged platelets and necrotic endothelial remnants were other components. These observations were interpreted as a result of glomerular stasis, and it was concluded that stasis in glomerular capillaries is a basic event in the development of the renal lesions accompanying the generalized Shwartzman reaction.
Circulating Dermatan Sulfate and Heparan Sulfate/Heparin Proteoglycans in Children Undergoing Liver Transplantation
Authors: Mitchell Lesley , Superina Ricardo , Delorme Michael , Vegh Patsy , Berry Leslle , Hoogendoorn Hugh , Andrew Maureen 
Published: July 2018

SummaryThe liver produces dermatan sulfate (DS), heparan sulfate (HS) and heparin glycosaminoglycans (GAG) and in the presence of hepatic disease, tissue levels of the DS GAG increase dramatically. We hypothesized that in children undergoing liver transplantation plasma levels of DS would be increased. Plasma from children undergoing liver transplantation were tested preoperative, intra operative and post operative at 24-48 h, and 1-3 weeks. Fluctuating levels of DS, HS and heparin anticoagulant activity were detected at all timepoints. The anticoagulant activity was purified and gel chromatography of the material displayed a mean Mr 110,000 D. Reductive elimination decreased the mean Mr 24,000 D indicating the activity resides on a proteoglycan (PG). The purified material was subjected to further chromatography and two peaks of anticoagulant activity resolved, compatible with at least two separate PGs, one with DS GAG chains and the additional PG(s) with HS and heparin GAG chains.
Characterization of the Structural Requirements for a Carbohydrate Based Anticoagulant with a Reduced Risk of Inducing the Immunological Type of Heparin-associated Thrombocytopenia
Authors: Greinacher Andreas , Alban Susanne , Dummel Veronika , Franz Gerhard , Mueller-Eckhardt Christian 
Published: July 2018

SummaryHAT is the most frequent drug induced immune-thrombocytopenia. We recently identified multimolecular PF4/heparin complexes as the major antigen. In order to evaluate the structural requirements for formation of the antigenic complex, we chemically synthesized 13 glucan sulfates and used 5 heparin fractions (2.4-4.8 kD) and a synthesized pentasaccharide, representing the antithrombin III binding sequence of heparin, to further characterize the HAT antigen. In the presence of glucan sulfates and heparin, HAT antibodies caused platelet activation typically at low but not at high concentrations, as measured by 14C-5HT release. The concentration range giving the activation pattern depended on the degree of sulfation (DS) and molecular weight (MW) of the glucan sulfates but not on the type of glycosidic linkage of a polysaccharide. With linear glucan sulfates with a chain length of 35 monosaccharides, the critical DS to form the HAT antigen ranged between 0.60 and 1.20. Glycosidic branched glucan sulfates were able to form the HAT antigen at a lower DS and a lower MW than linear glucan sulfates. Platelet activation by HAT-antibodies in the presence of linear curdlan sulfate fractions was dependent on their MW. At a low concentration (0.01 µM) medium-size fractions (60 kD) caused platelet activation but neither small (12 kD) nor large fractions (>150 kD) did. At higher concentrations (2 µM) the opposite reaction pattern was observed. In the case of heparin, the optimal chain length for forming the HAT antigen is a hexadecasaccharide (4.8 kD). Antigen generation decreased with larger and smaller fractions. For 50% platelet activation by HAT antibodies increasing concentrations of heparin were necessary using heparins with decreasing MW: 0.02 ± 0.015 µM (4.8 kD), 0.09 ± 0.016 pM (3.0 kD), 0.8 ± 0.21 µM (2.4 kD). In the presence of the pentasaccharide, HAT antibodies did not cause platelet activation atany concentration tested, nor bound to PF4-pentasaccha- ride complexes in a PF4 based ELISA system. We conclude that generation of the HAT antigen is dependent on the ratio of MW and DS of a glucan sulfate. We conclude from this study that a carbohydrate based anticoagulant with a reduced risk of forming the HAT antigen should be linear with a DS<0.6 or a MW <2.4 kD. These data might be important for the design of new drugs for parenteral anticoagulation.
Antigenic and Functional Expression of Tissue Factor in Endotoxin Stimulated U937 Cells: Regulation of Activity by Calcium Ionophore A23187
Authors: Consonni R , Bertina R M 
Published: July 2018

SummaryTissue Factor (TF) is a transmembrane glycoprotein that serves as cofactor for Factor VII (FVII) in the initiation of blood coagulation and that is differentially expressed in a number of cell types, being constitutively expressed in some and inducible in others. We studied the localization and the functional activity of TF in monocytic leukemia U937 cells at different time intervals after lipopolysaccharides (LPS) stimulation, and the effect of calcium ionophore on the surface expressed TF.Exposure of U937 cells to 10 µg/ml LPS resulted in a time dependent increase of TF expression that reached a maximum at 12 h for TF antigen and at 24 h for TF activity. Blocking of surface TF with inhibitory anti-TF antibody abolished >93% of the activity of lysed cells stimulated for 24 h, while it blocked only 80% of the activity in lysed cells stimulated for 12 h suggesting that at that time about 20% of TF is not accessible for the antibody. Even at 24 h when the specific activity of surface expressed TF is 5.5 times higher than at 12 h, this specific activity is still 10 fold lower than that of TF in lysed cells. Addition of Ca++ ionophore A23187 to LPS stimulated cells resulted in a fast increase of TF activity that was dependent on the dose of ionophore, on the extracellular Ca++ concentration and on the time that the cells had been incubated with LPS. Kinetic analysis of Factor X hydrolysis by the TF/FVII complex demonstrated that the addition of ionophore resulted in an increase of both the Vmax and the apparent Km, however, without affecting the catalytic efficiency of the reaction.These data suggest that in U937 cells part of the TF induced by LPS is cryptic, that the specific activity of surface expressed tissue factor increases with time and that intracellular changes in Ca++ concentration can be important in the regulation of the expression of TF activity on the cell surface.
Diagnosis of Hemophilia B Carriers Using Two Novel Dinucleotide Polymorphisms and Hha I RFLP of the Factor IX Gene in Japanese Subjects
Authors: Toyozumi Hisato , Kojima Tetsuhito , Matsushita Tadashi , Hamaguchi Motohiro , Tanimoto Mitsune , Saito Hidehiko 
Published: July 2018

SummaryWe identified two novel dinucleotide polymorphisms in intron A at nucleotide 192 (FIX 192) and in the 5’ flanking region at nucleotide -793 (FIX-793) of the factor IX gene, which are present in normal Japanese. The Hha I restriction fragment length polymorphism (FIX-Hhal) located 8 kb 3’ to the factor IX gene was also found to be an efficient marker for detecting carriers in a Japanese family with hemophilia B. Each of these polymorphisms was able to be rapidly ascertained by the polymerase chain reaction (PCR) technique. In 22 Japanese families with hemophilia B, 18 families (81.8%) were heterozygous for at least one of these polymorphisms, whereas 11 (50%) were informative for the extragenic DXS99/Sac I RFLP which was previously reported as a useful gene marker for Japanese hemophilia B. Using all 4 polymorphisms together, the informative rate improved to 86.4%. Carrier detection and, possibly, the prenatal diagnosis of hemophilia B can be achieved effectively and rapidly in Japanese with these polymorphisms.
Thromboxane Biosynthesis, Neutrophil and Coagulative Activation in Type IIa Hypercholesterolemia
Authors: Davì Giovanni , Ganci Antonina , Averna Maurizio , Giammarresi Carlo , Barbagallo Carlo , Catalano Isabella , Calà Anna , Notarbartolo Alberto 
Published: July 2018

SummaryThromboxane (Tx) A2 biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia. Because blood clotting activation is an important component of the inflammatory response, involved in the initiation and progression of atherosclerotic plaques, we have investigated TxA2 biosynthesis, neutrophil activation and thrombin generation in 24 patients with type IIa hypercholesterolemia.Urinary 11-dehydro-TxB2, was significantly higher (p =0.0001) in patients than in 24 sex- and age matched healthy subjects. Similarly, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin III complexes and plasma elastase were significantly higher in patients than incontrols. Urinary 11-dehydro-TxB2 excretion was correlated with plasma elastase (r = 0.758; p =0.000I), and prothrombin fragment 1+2 (r = 0.804; p = 0.001). The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor simvastatin (20 mg/day for 2 months) significantly reduced cholesterol levels, urinary 11-dehydro-TxB2 excretion, plasma elastase and plasma Fl+2 in 8 patients.We conclude that type IIa hypercholesterolemia is associated with biochemical evidence of platelet, neutrophil and blood clotting activation. The relationship between these events remains to be investigated.
Mechanisms of Platelet Dysfunction and Response to DDAVP in Patients with Congenital Platelet Function Defects
Authors: Rao A Koneti , Ghosh Sikha , Sun Ling , Yang Xu , Disa Jyoti , Pickens Peter , Polansky Marcia 
Published: July 2018

SummaryTo examine the impact of the underlying defective platelet mechanism on the response to 1-desamino-8-D-arginine vasopressin (DDAVP, Desmopressin), we studied the effect of intravenous infusion of 0.3 μg/kg of DDAVP in a randomized double blind placebo-controlled trial with cross-over in 18 carefully characterized patients with congenital platelet defects (CPD) and BT ≥9 min. Eleven patients had normal dense granule stores and normal thromboxane A2 (TxA2) production (Group I), 3 patients had normal granule stores but impaired TxA2 production (Group II), and 4 had δ-storage pool deficiency (Group III). DDAVP shortened BT at 50 min (DDAVP 14.6 ± 2.2 vs placebo 19.6 ± 2.3 min; n = 18; mean ± SE; p = 0.003) and 4h (17.0 ± 2.2 vs 19.6 ±2.1 min, p = 0.055), and raised plasma FVIIIC and von Willebrand factor (vWF). At 50 min DDAVP shortened BT by ≥5 min in 8 of 11 Group I patients (mean 9.7 ± 1.3 vs 16.3 ± 2.8 min; p <0.008), 1 of 3 Group II patients (11.9 ± 3.9 vs 17.7 ± 6.6; p = NS) and none of Group III patients (mean 30 min both arms). Ten patients (Group I or II) were managed successfully during surgical procedures with DDAVP alone. We conclude that DDAVP shortens BT in majority of CPD patients with normal dense granule stores and suggest that BT response may be dependent on the underlying platelet defect. DDAVP is a useful modality in management of selected patients, particularly those with normal dense granule stores.
Biological Effects of Combined Inactivation of Plasminogen Activator and Plasminogen Activator Inhibitor-1 Gene Function in Mice
Authors: Lijnen H Roger , Moons Lieve , Beelen Veerle , Carmeliet Peter , Collen Désiré 
Published: July 2018

SummaryMice with combined homozygous deficiency of tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA) (T‾U‾), of t-PA and plasminogen activator inhibitor-1 (PAI-1) (T‾P‾), of u-PA and PAI-1 (U‾P‾) or of t-PA, u-PA, and PAI-1 (T‾U‾P‾) were generated by inbreeding of mice with the respective deficiencies. Homologous recombination at the t-PA, u-PA and PAI-1 locus was verified by Southern blot analysis of genomic tail tip DNA, and confirmed by measurement of antigen levels in plasma or urine.T‾P‾ and U‾P‾ mice were apparently healthy and fertile. T‾U‾ mice showed extensive fibrin deposition with calcification in the liver, whereas T‾U‾P‾ mice were significantly (p <0.001) less affected. Spontaneous in vivo clot lysis measured 4 h after injection of a 125I-fibrin-labeled clot prepared from plasma of wild-type (WT) mice into the jugular vein, was (mean ± SEM of n experiments) 2 ± 1% (n = 8) for T P , 49 ± 6% (n = 9) for U‾P‾, 1 ± 1% (n = 4) for T‾U‾ and 3 ± 3% (n = 3) for TU‾P‾ mice, as compared to 32 ± 4% (n = 10) for WT, 1 ± 0% (n = 7) for T‾, 30 ± 5% (n = 5) for U‾ and 58 ± 10% (n = 6) for P‾ mice. Plasminogen-dependent lysis of 125I-fibrin-labeled matrix and of 3H-proline-labeled subendothelial matrix (mean ± SEM; n = 4 to 6) was lower with thioglycollate-stimulated macrophages obtained from U‾P‾ mice (22 ± 7% and 5 ± 1%, respectively), as compared to WT mice (57 ± 14% and 18 ± 5%, respectively) and T‾P‾ mice (87 ± 6% and 27 ± 4%, respectively). A similar decrease was previously observed with U‾ mice, but not with T‾ or P‾ mice. Thus, the phenotype of mice with combined deficiency of t-PA and PAI-1 or of u-PA and PAI-1 is similar to the phenotype observed in mice with single deficiency of the plasminogen activator. Additional deletion of PAI-1 does not affect viability, fertility, macrophage function or thrombolytic potential of the single deficient mice. Additional deletion of PAI in mice with combined deficiency of t-PA and u-PA does not restore the deficient in vivo fibrinolytic capacity, but significantly reduces the thrombotic phenotype, as revealed by fewer, smaller and less calcified fibrin deposits in the liver.
Inhibition of Platelet Aggregation by an SLE-Derived Human Hybridoma Autoantibody Against an Activation-Dependent Antigen
Authors: Xu H , Frojmovic M M , Wong T , Rauch J 
Published: July 2018

SummaryAnti-platelet autoantibodies may be responsible for hematological complications in patients with systemic lupus erythematosus (SLE), but the mechanisms by which these antibodies cause abnormal hemostasis remain unknown. In the present study, using fluorescence activated cell sorter (FACS) analysis, we demonstrate that an SLE-derived human hybridoma autoantibody, 9604, recognizes a surface antigen expressed on platelets activated by ADP, calcium ionophore A23187, or phorbol myristate acetate (PMA), showing saturation with approximately 2,000 antibody molecules bound per platelet and a Kd of 41 nM. The binding of 9604 to activated platelets was significantly inhibited by EDTA, indicating partial dependence on divalent cations. It did not appear to be dependent on platelet secretion, nor did it directly affect α-granule or dense granule secretion. The protein antigen responsible for the binding of 9604 to activated platelets was characterized by Western blot and immunoprccipitation and shown to have a native molecular weight (M. W.) of greater than 400,000, with a 32,000 M. W. subunit (p 32). Antibody 9604 had little or no effect on the shape change and the initial rate of primary aggregation of normal platelets. In contrast, 9604 inhibited secondary aggregation of stirred platelet suspensions (IC50 ≥1 nM) following activation by ADP, thromboxane A2 mimetic U46619, or calcium ionophore A23187, but not PMA or thrombin. The inhibition of large platelet aggregate formation (secondary aggregation), with a major shift to smaller microaggregates and singlets, was confirmed by direct particle count and sizing studies. The functional inhibition of platelet aggregation by an SLE-derived human hybridoma autoantibody in vitro suggests one potential mechanism that may play a role in the hemostatic disorders found in SLE.
Decreased Plasma Tissue Factor Pathway Inhibitor Levels in Patients with Thrombotic Thrombocytopenic Purpura
Authors: Wada Hideo , Kobayashi Masayuki , Wakita Yoshihiro , Shimura Minori , Nakase Tutomu , Hiyoyama Katsuyo , Nagaya Syousaburou , Minami Nobuyuki , Nakano Takeshi , Shiku Hiroshi 
Published: July 2018

SummaryWe measured plasma levels of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in patients with thrombotic thrombocytopenic purpura (TTP) and disseminated intravascular coagulation (DIC) to examine the relationship between TFPI and vascular endothelial cell injury. TF antigen was detected in the plasma of healthy volunteers, and the levels were significantly increased in the patients with DIC, but decreased slightly in those with TTP. Plasma TFPI levels were significantly decreased in patients with TTP compared with those in healthy volunteers. The concentration of plasma thrombomodulin (TM) antigen was significantly higher in those with TTP than in normal volunteers. One month after treatment, TTP patients showed a significant decrease in plasma TM levels, and a significant increase, in plasma TFPI levels, but plasma levels of TF antigen were not significantly increased. As plasma TFPI/TF ratio was significantly increased after treatment, the hypercoagulable state was therefore improved after treatment. There was no significant difference in plasma TF and TFPI levels between those who achieved complete remission (CR) and those who died. However, plasma TM levels were significantly higher in those who died than in those who achieved CR. Plasma TFPI levels might reflect injury of vascular endothelial cells as do plasma TM levels, and decreased plasma TFPI/TF ratio and vascular endothelial cell injuries might play causative roles in TTP.
Application of a Novel and Rapid Whole Blood Assay for D-Dimer in Patients with Clinically Suspected Pulmonary Embolism
Authors: Ginsberg Jeffrey S , Wells Philip S , Brill-Edwards Patrick , Donovan Dianne , Panju Akbar , van Beek Edwin J R , Patel Ameen 
Published: July 2018

SummaryStudy Objective: To determine the clinical utility of a novel whole blood assay for D-dimer (SimpliRED™) in patients with clinically suspected pulmonary embolism (PE).Design: Prospective cohort.Patients: Eighty-six consecutive patients with clinically suspected PE.Intervention: All patients had the SimpliRED D-dimer assay performed and underwent ventilation/perfusion (V/Q) lung scanning and bilateral impedance plethysmography (IPG); pulmonary angiography was performed in two patients. Patients were classified as: 1) PE-positive; positive pulmonary angiography or high probability V/Q scan or non-high probability V/Q scan and either abnormal IPG (either at presentation or upon serial testing and confirmed by contrast venography) or symptomatic thromboembolic event within three months of presentation or 2) PE-negative; normal V/Q scan or normal pulmonary angiography or non-high probability V/Q scan and normal serial IPG and absence of symptomatic venous thromboembolism within three months of follow up. Sixteen (19%) patients were classified as PE-positive and 70 (81%) patients were classified as PE-negative.Measurements and Result: The sensitivities, specificities, positive predictive values, and negative predictive values of the D-dimer assay were calculated for all patients and for the subgroup of patients without comorbid conditions that independently can cause elevated D-dimer levels. The D-dimer showed a sensitivity of 94%, a negative predictive value of 98%, a specificity of 66%, and a positive predictive value of 38%. In the subgroup of patients without comorbid conditions, the specificity increased to 98% and the positive predictive value to 83%, but because only six patients had an abnormal D-dimer level, the 95% confidence interval on the observed positive predictive value is wide (36-100%).Conclusions: This study demonstrates that the SimpliRED D-dimer assay, which can be performed and interpreted at the bedside within five minutes, has potential clinical utility as an exclusionary test in patients with clinically suspected PE. The assay should be evaluated in large clinical management studies.