bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Experimental Model of Intracranial Hemorrhage during Thrombolytic Therapy with t-PA
Authors: Paoni Nicholas F , Steinmetz Hope G , Gillett Nancy , Refino Canio J , Badillo Julie M , Bunting Stuart 
Published: July 2018

SummaryMultiple clinical trials have proven that thrombolytic therapy is an effective treatment for acute myocardial infarction. Spontaneous intracranial hemorrhage (ICH) occurs in a small percentage of patients as a result of the treatment. The etiology of the ICH is unknown and there is currently no established experimental model for this side effect. A model of ICH during thrombolytic therapy has been developed using spontaneously hypertensive rats (SHR). The SHR were made susceptible to ICH during thrombolytic therapy by bilateral ligation of the external jugular veins. This procedure produced asymptomatic hemorrhagic lesions in the brains of the animals in the hours preceding the administration of t-PA/heparin. The incidence of ICH following the administration of test substances was assessed by histological examination and by measuring the red blood cell count in a sample of cerebrospinal fluid taken from the atlanto-occipital space. t-PA administration produced a low frequency of ICH in this model. The incidence and severity of ICH were dramatically increased, and significant mortality at 24 h was observed, by combining heparin with the t-PA. No fewer hemorrhages were observed if the t-PA and heparin were administered sequentially rather than simultaneously. Furthermore, ICHs were observed whether the t-PA dose was administered over 4 h, 1 h, or as a double bolus 30 min apart. The potentiation of ICH by heparin was dose dependent and proportional to the prolongation of the aPTT. Although the precise mechanism of ICH during thrombolytic therapy is unknown, many similarities exist between the observations made in this model and in the human clinical experience.
Venous Thrombosis and the “Wessler Test”
Authors: Thomas Duncan P 
Published: July 2018

SummaryThe Wessler test in animals has been used extensively for over 40 years as a laboratory measure of in vivo hypercoagulability. The test, in which induced hypercoagulability is combined with local venous stasis, has contributed significantly to our understanding of the pathogenesis of venous thrombosis and pulmonary embolism. In addition, the Wessler test has proved invaluable for assessing the thrombogenicity of various blood products, as well as for assaying the effectiveness of heparin and heparin fractions.
Evaluation of the Fibrin Binding Profile of two Anti-fibrin Monoclonal Antibodies
Authors: Raut S , Gaffney P J 
Published: July 2018

SummaryTwo anti-fibrin monoclonal antibodies, MAbs 1H10 and 5F3, raised to human freeze-fractured fibrin and thrombin-treated N-terminal disulphide knot (T-NDSK), respectively, were compared for epitope binding to various domains of the fibrinogen/fibrin moiety. Using plasmin-mediated fibrinogen digests, immunoblots showed that both MAbs crossreacted strongly with fragments X and Y, weakly with fragment-E and not at all with fragment D. Purified fragments D and E used in an ELISA confirmed that MAbs 1H10 and 5F3 cross-reacted in a dose-response fashion with the isolated fragment-E, while there was no reaction with fragment-D. The two MAbs were similarly shown to react with fibrin-derived fragment-E. Surface Plasmon Resonance (SPR) technology, employed to further evaluate the epitopes in fibrin, showed that MAb 1 HI0 had a higher affinity for fragment-E (KD = 8.04 × 10-9 M) than MAb 5F3 (KD = 1.13 × 10-8 M). Individual association and dissociation rate constants of 7.97 × 105 M-1S-1 and 3.97 × 10-3S-1, respectively, for MAb 1H10, and 5.16 × 105 M-1s-1 and 3.62 × 10-3s-1, respectively, for MAb 5F3 were also obtained. A SPR inhibition assay confirmed that MAb 1H10 had a greater affinity for fragment-E than MAb 5F3. However individual isolated polypeptide chains of fibrinogen fragment E (E-Aα, E-Bβ, E-γ) showed no reaction with the two antibodies in ELISA, immunoblot or SPR analysis procedures. Furthermore, SPR pair-wise epitope mapping analysis revealed that MAbs 1H10 and 5F3 have in fact distinct epitopes on fragment-E. These distinct epitopes appeared to be a conformational amalgam of linear sequences in two or three of the polypeptide chains of fragment-E, or distinct conformational epitopes on one of the three subunit chains alone.
Liver Steatosis and Its Relation to Plasma Haemostatic Factors in Apparently Healthy Men - Role of the Metabolic Syndrome
Authors: Cigolini M , Targher G , Agostino G , Tonoli M , Muggeo M , De Sandre G 
Published: July 2018

SummaryThe relationship between liver steatosis, evaluated by ultrasonography, and various plasma haemostatic factors was examined in 64 apparently healthy males, aged 38 years. Plasma levels of factor VII clotting activity (F-VIIc), plasminogen activator inhibitor-1 (PAI-1) activity and antigen, tissue-type plasminogen activator (t-PA) activity significantly differed in men with liver steatosis (n = 31) as compared with those without steatosis (n = 33). No significant differences were found in t-PA antigen and F-VII antigen. The men with liver steatosis also had significantly higher body mass index (BMI), plasma triglyceride and 2 h post-load insulin concentrations. While the differences in plasma haemostatic factors were substantially unchanged after adjustment for BMI, they totally disappeared when further allowance was made for plasma triglyceride and 2 h insulin concentrations. In conclusion, these results indicate that liver steatosis correlates specifically with increased PAI-1, F-VIIc and decreased t-PA levels, and suggest that such a relation is largely mediated by concomitant alterations in plasma triglyceride and insulin concentrations.
Three Different Cell Types Can Synthesize Factor XIII Subunit A in the Human Liver
Authors: Ádány Róza , Antal Miklós 
Published: July 2018

SummaryThe origin of human Factor XIII subunit A (FXIII A) has been a subject of intense speculation and investigation during the last decade. The major question under dispute is whether hepatocytes can produce this clotting factor. Experimental evidence obtained by FXIII A phenotype analysis in bone marrow transplant patients clearly identified hemopoietic cells (monocytes/macrophages and/or megakaryocytes/ platelets) as a source of FXIII A, and also showed that additional extra-hemopoietic site(s) of synthesis also exist. The liver has been suggested as a possible extrahemopoietic source of plasma FXIII A, but the cells responsible for synthesizing FXIII A were not identified yet. Our present study was designed to determine the cellular distribution of both FXIII A and its encoding mRNA in human liver samples by using light- and electron-microscopic immuno-morphological and in situ hybridization techniques. In paraformaldehyde/glutaraldehyde (PA/GA) fixed, araldite-embedded semithin sections that were immunostained by an ABC/DAB based postembedding immunocytochemical method, FXIII A could be detected in Kupffer cells, connective tissue histiocytes and hepatocytes. Immunoreactive hepatocytes were observed almost exclusively around the venae centrales. By using postembedding immunogold labeling, FXIII A could be electron-microscopically visualized in these hepatocytes in the immediate vicinity of the lamellae of the endoplasmic reticulum. By in situ hybridization using a mixture of five 32-40mer biotinylated oligonucleotides (ONs) to mRNA regions encoded by exons VI, XI and XV and a labeling system containing streptavidin conjugated with alkaline phosphatase/BCIP/NBT, the message for FXIII A could be detected in the same cell types. These results show that in human liver three different types of cells can synthesize FXIII A, but the extent of their contribution to the plasma FXIII A level will require further studies.
Gemfibrozil Reduces Thrombin Generation in Patients with Combined Hyperlipidaemia, without Influencing Plasma Fibrinogen, Fibrin Gel Structure or Coagulation Factor VII
Authors: Bröijersén Anders , Hamsten Anders , Silveira Angela , Fatah Kamaran , Goodall Alison H , Eriksson Sabina , Angelin Bo , Hjemdahl Paul 
Published: July 2018

SummaryA double-blind, placebo-controlled, cross-over study was conducted in 21 men with combined hyperlipoproteinaemia to examine if lipid-lowering treatment with gemfibrozil (10-12 weeks) affects blood coagulation and fibrin gel structure at rest or during mental stress. Gemfibrozil lowered plasma triglycerides by 57 ± 4%, whereas high density lipoprotein (HDL) cholesterol increased by 22 ± 5%. Gemfibrozil lowered the triglyceride content of low density lipoprotein (LDL). Gemfibrozil reduced the plasma concentrations of thrombin-antithrombin complex (TAT) and prothrombin fragment F1+2 (F1+2), both at rest and during mental stress. However, there were no effects of gemfibrozil treatment on the plasma concentrations of fibrinogen, factor VII antigen, activated factor VII (Vila) or activated factor XII (XIIa), or on fibrin gel structure. Acute mental stress per se did not influence coagulation factors, reaction products or fibrin gel structure, or their responses to the study drug. Thus, gemfibrozil reduces thrombin generation in men with combined hyperlipoproteinaemia, without influencing the plasma levels of fibrinogen, Vila and XIIa, or fibrin gel structure. Attenuation of thrombin generation may contribute to the primary-preventive effects of gemfibrozil on coronary heart disease.
Coagulation Activation and Fibrinolytic imbalance in Subjects with Idiopathic Antiphospholipid Antibodies -A Crucial Role for Acquired Free Protein S Deficiency
Authors: Ames Paul R J , Tommasino Catello , Iannaccone Luigi , Brillante Massimo , Cimino Renato , Brancaccio Vincenzo 
Published: July 2018

SummaryTo explore the coagulation/fibrinolytic balance and its relation with free protein S (f-PS) in subjects with antiphospholipid antibodies (aPLs) outside the setting of autoimmune inflammatory disorders, we carried out a cross-sectional study on 18 thrombotic patients with primary antiphospholipid syndrome and 18 apparently healthy subjects with persistence of idiopathic aPLs. Prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT) and D-Dimer (D-D) were taken as markers of thrombin generation and fibrin turnover. Mean F1+2 levels were higher in thrombotic (p = 0.006) and non-thrombotic subjects (p = 0.0001) than in controls as were those of D-D (p <0.0001 and p = 0.003 respectively). TAT levels did not differ. Lower mean levels of f-PS were found in thrombotic (p = 0.0006) and non-thrombotic subjects (p = 0.002) than in controls. Within both groups, mean Fl+2 levels were higher in subjects who had low f-PS levels compared to those with normal f-PS levels (p = 0.01). Gender analysed data revealed blunted tPA release (venous occlusion test) in thrombotic females (from 16.80 ± 0.79 to 21.3 ± 3.9 ng/nl, NS) but not in thrombotic males (from 18.2 ± 2.0 to 33.7 ± 4.9 ng/ml, p = 0.01) nor in asymptomatic subjects of either sex. Also, in both patient groups females had higher mean PAI than males (p <0.0002) and than control females (p <0.02). Low free protein S was found in 100% of non-thrombotic and in 90% of thrombotic patients with defective fibrinolysis. These data are consistent with increased thrombin generation, accelerated fibrin turnover and fibrinolysis abnormalities also in asymptomatic carriers of aPLs and highlight a central role for acquired f-PS deficiency in the thrombotic tendency of the antiphospholipid syndrome.
Immunological Aspects of Recombinant Factor Vila (rFVIIa) in Clinical Use
Authors: Nicolaisen Else Marie , Hansen Lisbeth Lyng , Poulsen Fritz , Glazer Steven , Hedner Ulla 
Published: July 2018

SummaryPatients, receiving rFVIIa for treatment of bleeding disorders, have been followed for specific antibody formation. No antibodies against FVII were demonstrated in 170 patients, with hemophilia, or with acquired inhibitors to clotting factors. Of 6 FVII-deficient patients, one overdosed patient developed antibodies to human FVII. There was no indication of de novo formation of antibodies to potential contaminating foreign protein, which could be correlated to the rFVIIa treatment. Except for the FVII-deficient population, which may represent a risk group, rFVIIa appears to be immunologically safe for use in patient groups with bleeding disorders, including hemophilia A and B patients.
Tissue Factor Pathway Inhibitor Production by Human Mesangial Cells in Culture
Authors: Yamabe H , Osawa H , Inuma H , Kaizuka M , Tamura N , Tsunoda S , Fujita Y , Shirato K , Onodera K 
Published: July 2018

SummaryFibrin formation within the glomeruli has been observed in various forms of human and experimental glomerulonephritis and it may play an important role in progressive glomerular injury. Furthermore it has been hypothesized that glomerular fibrin deposition may occur through activation of either the intrinsic or extrinsic coagulation pathway. It has been demonstrated that a procoagulant activity (PCA) which is compatible with tissue factor is present in the glomeruli and becomes increased in human proliferative glomerulonephritis and in animal models of nephritis. Tissue factor pathway inhibitor (TFPI) regulates the extrinsic pathway of blood coagulation through its ability to inhibit tissue factor activity. TFPI is present in plasma and in platelets, and it is now thought to be produced mainly by endothelial cells. We examined whether human mesangial cells (HMC) could produce TFPI and attempted to clarify regulatory factors which affect TFPI production. Cultured HMC were used and TFPI in the cell supernatants was measured by ELISA using a specific antibody. Cultured HMC showed the production of TFPI. Immunoblot analysis revealed 40 kD protein of TFPI. The concentration of TFPI was significantly increased following the incubation with thrombin and heparin, including low molecular weight heparin, in a dose- and time-dependent manner. However, fetal calf serum, phorbol myristate acetate, lipopolysaccharide, IL-1β and tissue factor did not stimulate TFPI synthesis. Our data show that cultured HMC have the ability to produce TFPI which inhibits fibrin formation. It is possible that thrombin-induced enhancement of TFPI synthesis may be caused by the autoregulatory system of blood coagulation and that with heparin it may represent another anticoagulatory effect of heparin.
The VITA Project: Population-based Distributions of Protein C, Antithrombin III, Heparin-cofactor II and Plasminogen -Relationship with Physiological Variables and Establishment of Reference Ranges
Authors: Rodeghiero Francesco , Tosetto Alberto 
Published: July 2018

SummaryA proper laboratory diagnosis of inherited thrombophilia due to defects of the coagulation system may be obtained only by a stringent definition of the diagnostic reference ranges taking into account the influence exerted by major physiological variables. To this purpose, we analyzed the data for Protein C, Antithrombin III, Heparin-Cofactor II and plasminogen coming from the first 4,000 subjects enrolled in the VITA Project. This is the first study that allows the establishment of reference ranges in a non-selected, active population using stringent standardization of clinical and laboratory measurements and multivariable regression techniques for data analysis.Serum triglycerides and total cholesterol, together with plasma fibrinogen were found to influence the functional plasma level of the four considered proteins. Menopause increased AT-III concentration, while pill use increased Heparin-Cofactor II and plasminogen. PT and PTT ratio, gender, age, smoking, body-mass index, HDL cholesterol and blood group had minor effects. The effect of these variables should be taken into account for both clinical and epidemiologic purposes, using appropriate reference ranges or covariance analysis for adjustment.
lonomycin-stimulated Arachidonic Acid Release in Human Platelets: a Role for Protein Kinase C and Tyrosine Phosphorylation
Authors: Hargreaves Philip G , Jenner Susanne , Merritt Janet E , Sage Stewart O , Farndale Richard W 
Published: July 2018

SummaryCollagen (10-90 Μg/ml) and ionomycin (1 ΜM; a calcium iono-phore) each evoked rises in intracellular free calcium, protein kinase C activity and arachidonic acid release in human platelets, and as previously demonstrated for collagen, ionomycin (1 p,M) stimulated protein tyrosine phosphorylation. However, at lower concentrations (60 and 250 nM) ionomycin selectively mobilised calcium. Ro31-8220 (a selective inhibitor of protein kinase C) inhibited (by 50%) ionomycin-stimulated arachidonic acid release. Genistein (an inhibitor of protein tyrosine kinases) also reduced by 50% ionomycin-stimulated arachidonic acid release. In combination, genistein and Ro31-8220 abolished ionomycin-stimulated arachidonic acid release. These findings show 1) that a rise in calcium is not sufficient, and 2) the activation of both protein kinase C and protein tyrosine phosphorylation is necessary, for full ionomycin-stimulated arachidonic acid release in human platelets.
A Novel Mutation Glyl672→Arg in Type 2A and a Homozygous Mutation in Type 2B von Willebrand Disease
Authors: Hagiwara Takeshi , Inaba Hiroshi , Yoshida Shinichi , Nagaizumi Keiko , Arai Morio , Hanabusa Hideji , Fukutake Katsuyuki 
Published: July 2018

SummaryGenetic materials from 16 unrelated Japanese patients with von Willebrand disease (vWD) were analyzed for mutations. Exon 28 of the von Willebrand factor (vWF) gene, where point mutations have been found most frequent, was screened by various restriction-enzyme analyses. Six patients were observed to have abnormal restriction patterns. By sequence analyses of the polymerase chain-reaction products, we identified a homozygous R1308C missense mutation in a patient with type 2B vWD; R1597W, R1597Q, G1609R and G1672R missense mutations in five patients with type 2A; and a G1659ter nonsense mutation in a patient with type 3 vWD. The G1672R was a novel missense mutation of the carboxyl-terminal end of the A2 domain. In addition, we detected an A/C polymorphism at nucleotide 4915 with HaeIII. There was no particular linkage disequilibrium of the A/C polymorphism, either with the G/A polymorphism at nucleotide 4391 detected with Hphl or with the C/T at 4891 detected with BstEll.
Ala244Val Is a Common, Probably Ancient Mutation Causing Factor VII Deficiency in Moroccan and Iranian Jews
Authors: Tamary Hannah , Fromovich Yonit , Shalmon Lea , Reich Ziv , Dym Orly , Lanir Naomi , Brenner Benjamin , Paz Michael , Luder Anthony S , Blau Orit , Korostishevsky Michael , Zaizov Rina , Seligsohn Uri 
Published: July 2018

SummaryWe investigated the molecular basis for factor VII (FVII) deficiency in Israel and found that 13 patients were homozygous and 10 heterozygous for a C to T substitution at nucleotide 10648 of the FVII gene. This predicted an Ala244Val change and was associated with decreased FVII activity and antigen level. Of the 36 Ala244Val positive alleles, 20 were observed in patients of Moroccan origin, 10 in Iranian-Jewish patients and 6 in patients of other origins. A computer model of the serine protease domain of FVII suggested that the Ala244Val substitution may cause distortion of the entire protein structure. Intragenic polymorphic sites analyses disclosed a founder effect for the Moroccan and Iranian-Jewish patients. A survey of the Ala244Val mutation revealed an allele frequency of 1:42.5 in Moroccan Jews and 1:40 in Iranian Jews. As Moroccan Jews have been separated from Iranian Jews for more than two millennia, the data suggest that the Ala244Val mutation occurred in ancient times.
Genetic Characterization of Protein C Deficiency in Japanese Subjects Using a Rapid and Nonradioactive Method for Single-Strand Conformational Polymorphism Analysis and a Model Building
Authors: Miyata Toshiyuki , Sakata Toshiyuki , Zheng Yan-Zhen , Tsukamoto Hiroaki , Umeyama Hideaki , Uchiyama Shinichiro , Ikusaka Masaomi , Yoshioka Akira , Imanaka Yasufumi , Fujimura Hironobu , Kambayashi Jun-ichi , Kato Hisao 
Published: July 2018

SummaryWe studied the molecular basis of protein C deficiency in 28 Japanese families including 4 asymptomatic families. Two showed a decreased level of function with a normal antigen concentration consistent with type II protein C deficiency and the remaining 26 showed type I deficiency with decreases in both function and antigen level. All the exons and intron/exon junctions of the protein C gene were studied using a strategy combining polymerase chain reaction (PCR) amplification and rapid nonradioactive single-strand conformational polymorphism (SSCP) analysis. The PCR-amplified fragments with aberrant migration on SSCP analysis were sequenced. We identified 11 missense mutations, 1 nonsense mutation, 2 neutral polymorphisms, 1 frameshift deletion, 1 inframe deletion, and 1 splice site mutation. We also identified two different rare mutations in the 5-untranslated region in the protein C gene that may be responsible for the phenotype. Of these molecular defects, ten were novel. From the results of genetic analysis of 47 Japanese families with protein C deficiency reported in this and previous studies, Phel39Val and Met364Ile substitutions and a G8857 deletion were only found in Japanese subjects and seem to be a founder effect. In contrast, Argl69Trp and Val297Met substitutions, both occurring at CG dinucleotides, were commonly observed in not only Japanese but also Western populations, indicating that these are hot spots for mutation in the protein C gene. These molecular defects were found in 22 families in total, accounting for 47% of Japanese families with protein C deficiency. The structural models of the second EGF and protease domains of activated wild-type and mutant human protein C suggest a possible substrate binding exosite on two loops; one from amino acid position 349 to 357 and the other from position 385 to 388, both of which are close to each other in the three-dimensional model.
Increased Procoagulant Activity of Red Blood Cells from Patients with Homozygous Sickle Cell Disease and β-Thalassemia
Authors: Helley Dominique , Eldor Amiram , Girot Robert , Ducrocq Rolande , Guillin Marie-Claude , Bezeaud Annie 
Published: July 2018

SummaryIt has recently been proved that, in vitro, red blood cells (RBCs) from patients with homozygous β-thalassemia behave as procoagulant cells. The procoagulant activity of β-thalassemia RBCs might be the result of an increased exposure of procoagulant phospholipids (i. e. phosphatidylserine) in the outer leaflet of the membrane. In order to test this hypothesis, we compared the catalytic properties of RBCs of patients with β-thalassemia and homozygous sickle cell disease (SS-RBCs) with that of controls. The catalytic parameters (Km, kcat) of prothrombin activation by factor Xa were determined both in the absence and in the presence of RBCs. The turn-over number (kcat) of the reaction was not modified by normal, SS- or (3-thalassemia RBCs. The Km was lower in the presence of normal RBCs (mean value: 9.1 µM) than in the absence of cells (26 µM). The Km measured in the presence of either SS-RBCs (mean value: 1.6 µM) or β-thalassemia RBCs (mean value: 1.5 pM) was significantly lower compared to normal RBCs (p <0.001). No significant difference was observed between SS-RBCs and p-thalassemia RBCs. Annexin V, a protein with high affinity and specificity for anionic phospholipids, inhibited the procoagulant activity of both SS-RBCs and (3-thalassemia RBCs, in a dose-dependent manner. More than 95% inhibition was achieved at nanomolar concentrations of annexin V. These results indicate that the procoagulant activity of both β-thalassemia RBCs and SS-RBCs may be fully ascribed to an abnormal exposure of phosphatidylserine at the outer surface of the red cells.