bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antibody to Hepatitis G Mrus after a Vapour-Heated Factor Vlll Goncentrate
Authors: Mannucci P M , Zanetti A R , Colombo M , Chistolini A , De Biasi R , Musso R , Tamponi G ,   the Study Group of the Fondazione deii–Emofilia
Published: July 2018

SummaryTo evaluate whether or not clotting factor concentrates
exposed to virucidal procedures transmitted hepatitis C, sera obtained in 1984–1986 from 27 previously untreated hemophiliacs infused with a vapour-heated factor VIII concentrate were tested retrospectively for the antibody to the hepatitis C virus (anti- HCV). A 2-year-old hemophiliac, negative for anti-HCV before administration of concentrate, seroconverted at week 12 and remained anti-HCV positive thereafter. Both his parents were anti-HCV negative and he had no other household contact. The patient had also become HBsAg positive at week 8 and had at the same time a marked elevation of alanine aminotransferase. His double infection with the hepatitis B and C viruses indicates that hot vapour was not completely effective in inactivating these viruses.
Localization and Biosynthesis of Functional Thrombomodulin in Human Megakaryocytes and a Human Megakaryoblastic Cell Line (MEG-01)
Authors: Ogura Michinori , Ito Takahiko , Maruyama Ikuro , Takamatsu Junki , Yamamoto Shuji , Ogawa Kohei , Nagura Hiroshi , Saito Hidehiko 
Published: July 2018

SummaryThe localization and biosynthesis of functiosnal thrombomodulin (TM) on the cell surfaces of human platelets, megakaryocytes and a human megakaryoblastic cell line (MEG-01) were investigated. TM was demonstrated on the cell surfaces and in cytoplasms of human platelets, megakaryocytes and MEG-01 by an indirect immunofluorescent technique using monospecific rabbit anti-human TM serum. Immunoelectronmicroscopic analysis revealed that TM was localized in plasma membranes of MEG-01 cells as well as human megakaryocytes. 125I-monoclonal antithrombomodulin IgG binding assay showed that one MEG-01 cell possessed approximately 78,000 TM molecules on its cell surface. Thrombin-dependent protein C activating-cofactor activity was demonstrated on MEG-01 cells. Northern hybridization technique using cDNA probe of TM revealed that poly(A)+-RNA from MEG-01 cells showed a single band of 3.8 kb similar to that from human endothelial cells. These data suggest that human megakaryocytes synthesize functional TM, and thereby platelets possess TM on their surfaces. TM on platelets may participate in the activation of protein C at the site of a hemostatic plug.
Point Mutations in Four Hemophilia B Patients from China
Authors: Wang N S , Chen S H , Thompson A R 
Published: July 2018

SummaryPoint mutations in factor IX genes of four unrelated Chinese patients with hemophilia B have been identified by direct sequencing of amplified genomic DNA fragments. These four mutations occur in exon 8 of the factor IX gene. A C to T transition at nucleotide 30,863 changes codon 248 from Arg (CGA) to a new Stop codon (TGA), described in a previous family as factor IXMalmo3 (Green P M et al., EMBO J 1989; 8: 1067). A G to A transition, at nucleotide 31,051 changes codon 310 from Trp (TGG) to a nonsense or Stop codon (TGA; factor IXchongqing2)- A G to A transition at nucleotide 31,119 changes codon 333 which is for Arg (CGA) in normal factor IX, to one for Gin (CAA) in the variant previously described as factor IXLondon2 (Tsang T C et al., EMBO J 1988; 7: 3009) in a patient with moderately severe hemophilia B. The fourth patient has a novel C to A transversion at nucleotide 31,290, which corresponds to replacement of codon 390 which is for Ala (GCA) in normal factor IX, to one for Glu (GAA) in a patient with moderately severe hemophilia B (factor IXChongqing3)- DNA sequences of amplified fragments from mothers of three showed both their son’s variant and a normal nucleotide at the appropriate position, indicating that they are carriers. The fourth patient’s (factor IXMalmo3) mother, whose DNA was not evaluable, was most probably a carrier because of her low plasma factor IX levels.
Selenium Dependent Glutathione Peroxidase: A Physiological Regulatory System for Platelet Function
Authors: Perona G , Schiavon R , Guidi G C , Veneri D , Minuz P 
Published: July 2018

SummaryIn human platelets the selenoenzyme glutathione peroxidase (GSH-Px) acts as a scavenger of the peroxides generated during the burst of arachidonic acid (AA) metabolism. Such a mechanism inhibits the biosynthesis of both thromboxane A2 (TXA2) and lipoxygenase products. The same mechanism is not effective on the prostacyclin (PGI2) biosynthesis from cultured endothelial cells. In order to evaluate this effect in vivo, besides in vitro, we activated the enzyme in eight normal volunteers by increasing their daily Se intake for 8 weeks, monitoring: platelet GSH-Px activity, platelet aggregation induced by A A and U 44069, and concurrent malondialdehyde (MDA) and thromboxane B2 (TXB2) production, urinary excretion of renal and systemic TXA2 and PGI2 metabolites, platelet enzyme activities of the hexose monophosphate pathway and glutathione content, platelet adenine nucleotides, bleeding time, plasma Se concentration. We found: a) progressive platelet GSH-Px activation by Se paralleling an enhancement of platelet aggregation threshold values for AA, but not for U 44069; b) concurrent inhibition of platelet biosynthesis of TXA2 both in vitro and in vivo while the biosynthesis of systemic prostacyclin was unaffected; c) a progressive increase in the bleeding time, unmodified by aspirin. In conclusion, we believe that Se-dependent GSH-Px represents a physiological mechanism regulating the biosynthesis of prostanoids with implications in platelet function and that a Se dietary supplement might be considered in the prevention of arterial thrombosis.
Subcutaneous Desmopressin (DDAVP) Shortens the Prolonged Bleeding Time in Patients with Liver Cirrhosis
Authors: Cattaneo Marco , Tenconi Paola M , Alberca Ignazio , Garcia Vicente Vicente , Mannucci Pier Mannuccio 
Published: July 2018

SummaryThe intravenous infusion of 1-deamino-8-D-arginine vasopressin (DDAVP) shortens the prolonged bleeding time in patients with congenital or acquired bleeding disorders, including patients with uremia or liver cirrhosis. We carried out a double-blind, placebo-controlled crossover study in ten patients with liver cirrhosis to evaluate whether or not their prolonged bleeding times could be shortened by subcutaneous injections of DDAVP (0.3 μg/kg), a more practical route of administration than intravenous infusions. One hour after DDAVP injection the bleeding time was significantly shortened (p <0.05). After 4 h, however, the bleeding time shortening was no longer statistically significant. There was no bleeding time change after placebo. Plasma levels of von Willebrand factor antigen (vWF: Ag) did not significantly increase after DDAVP or placebo. The study shows that subcutaneous DDAVP is an alternative method for shortterm shortening of the bleeding time in liver cirrhosis.
A Specific Thromboxane Receptor Blocking Drug, AH23848, Reduces Platelet Deposition on Vascular Grafts in Man
Authors: Lane I F , Lumley P , Michael M F , Peters A M , McCollum C N 
Published: July 2018

SummaryThe antithrombotic effect of a specific thromboxane A2 receptor blocking drug, AH23848, on radio-labelled platelet deposition in mature Dacron aorto-bifemoral grafts has been evaluated in patients. Thirty patients were randomly allocated to AH23848 70 mg, aspirin 300 mg plus dipyridamole 75 mg or placebo 8-hourly for 9 days. AH23848 inhibited platelet aggregarion induced by the thromboxane ,A2 mimetic U-46619; no such effect was observed with aspirin plus dipyridamole. 111In-platelet uptake was measured as the thrombogenicity index (TI) which is a measure of the daily rate of accumulation of platelets by the graft. The mean (s.e. mean) value of 0.193 (0.029) on placebo was significantly reduced to 0.115 (0.022) by AH23848 (p <0.05) but only to 0.175 (0.028) by aspirin plus dipyridamole. There was no difference in mean platelet life span between the three treatment groups. The pronounced antithrombotic effect of AH23848 implicates thromboxane ,A2 in the process of platelet deposition in arterial prostheses and demonstrates the considerable promise of thromboxane receptor blocking drugs as antithrombotic therapy.
A Collaborative Study to Establish a Standard for High Molecular Weight Urinary-Type Plasminogen Activator (HMW/u-PA)
Authors: Gaffney P J , Heath A B 
Published: July 2018

SummaryAn international collaborative study involving eleven laboratories located in eight countries was undertaken to establish an International Standard for high molecular weight urinary-type
plasminogen activator (HMW/u-PA). The current International Reference Preparation (IRP code numbered 66146) for urinarytype plasminogen activator (u-PA) ot urokinase (see Nomenclature footnote) is a 66/34 molar ratio mixture of low molecular weight (LMW) - and high molecular weight (HMW) - u-PA’s and is considered unsuitable as a standard for homogeneous preparations of HMW/u-PA. The putative standard for HMWu-PA (code number, 87/594) was compared for potency in a clot lysis
assay with the current IRP for u-PA (code numbet, 66146) and a lyophilised preparation of single chain urinary-type plasminogen activator (SCuPA), the latter being used in the assay without
prior activation by plasmin to its active two chain form (TCuPA).Both the proposed standard for HMWu-PA (871594) and the SCuPA compared in a statistically satisfactory manner in parallel line bioassays with the current IRP for u-PA (66146), thus allowing potency estimates to be obtained for these two materials in relation to defined international units. Data from the eleven laboratories indicated that each ampoule of the proposed standard for HMWu-PA contained 4,300 i. u. of activity and was stable for over 1 year at 4° C. Most participants indicated that SCuPA expressed only a small amount of its activity without a prior activator step and this suggests that SCuPA assays need to be preceded by a plasmin activation stepThe Expert Committee on Biological Standardization of the World Health Organisation (Geneva, Oct 1989) established 871 594 as the International Standard for high molecular weight two chain urinary type plasminogen activator (HMW/TCuPA, of HMWu-PA), with an assigned unitage of 4,300 international units per ampoule.
Correlation between Progressive Adsorption of Plasminogen to Blood Clots and Their Sensitivity to Lysis
Authors: Sabovic M , Lijnen H R , Keber D , Collen D 
Published: July 2018

SummaryThe binding of plasminogen to preformed human plasma clots immersed in citrated human plasma was measured and correlated with the sensitivity of these clots to lysis with recombinant tissuetype plasminogen activator (rt-PA), recombinant single-chain urokinase-type plasminogen activator (rscu-PA) or two chain urokinase-type plasminogen activator (tcu-PA, urokinase)When 0.15 ml plasma clots were compressed mechanically to about 1% of their original weight, and immersed in 0.15 ml plasma, 131I-labeled native plasminogen (Glu-plasminogen) adsorbed progressively from the plasma milieu onto the clot; binding was 3 ± l% (, - 10) after 1 h, 7 ± L% after 12h and
12 ± l% after 48 h. This was associated with an increased sensitivity of the clot to lysis; 50% clot lysis in 4 h was obtained with 65 ± 5 ng/ml (n= 3) rt-PA before and 30 ± 5 ng/ml (n = 3) after 48 h preincubation in plasma (p <p 0.01), with corresponding values of 660 ± 55 ng/ml (n = 3) and 280 125 ng/ml (n = 3) for rscu-PA, (p < 0.01), ind 800 ± 85 nglml (n = 3) and 270 ± 35 ngt ml (n = 3) for urokinase (p < 0.01). Additional binding of plasminogen and increased sensitivity to lysis were reduced or abolished when the clot was preincubated in plasminogendepteted or in t-PA-depleted plasma, of when 20 mM 6-aminohexanoic acid or 2,000 KIU/ml aprotinin were added. When 0.1- ml retracted whole blood clots were preincubated in 1- ml plasma, 50% clot lysis in 4h was obtained with 1,150 ±
L60 ng/ml (n = 3) rt-PA before incubation and 55 ± 10 ng/ml (n = 3) after 48 h preincubation (p < 0.01), with corresponding values of 3,200 ± 430 ng/ml (n = 3) and 190 ± 30 ng/ml (n = 3) for rscu-PA (p < p0.01), and > 1,600 ng/ml and 220 ± 2A ng/ml (n = 3) for urokinase.These results show that preincubation of compressed plasma clots or retracted whole blood clots in plasma causes a progressive increase in both the binding of plasminogen and the sensitivity to lysis with plasminogen activators. Increased plasminogen binding may be the result of partial fibrindigestion.
Continuous Flow and the Prothrombinase-Catalyzed Activation of Prothrombin
Authors: Schoen Pieter , Lindhout Theo , Willems George , Coenraad Hemker H 
Published: July 2018

SummaryThe activation of prothrombin by prothrombinase was investigated in a continuous flow system at 25 °C. A glass capillary, containing a continuous phospholipid bilayer attached to the interior surface, was first perfused with factor Va. The factor Va bound to the phospholipid surface functioned as sites for the formation of prothrombinase, when subsequently a factor Xa and prothrombin containing solution was perfused. Under the conditions used, steady-state rates of prothrombin activation were attained after 4 to 15 min. The rates of prothrombinase formation increased with increasing factor Xa concentrations and flow rates, which is compatible with the assembly of prothrombinase being dependent on the flux of factor Xa to the phospholipid-bound factor Va. As long as factor Xa and prothrombin were present in the fluid phase the assembly of prothrombinase was apparently irreversible; during at least 20 min no loss of activity occurred. The steady-state rate of prothrombin activation was dependent on the surface concentration of prothrombinase, at 1.0 ΜM prothrombin and a shear rate of 82 s−1 the average rate was 870 mol thrombin/min per mol prothrombinase. In contrast to test tube experiments it was observed that in this flow system, the formation of Α-thrombin is favoured above the formation of meizothrombin (des fragment 1).
The pH Dependence of the Binding of Pro-Urokinase to Fibrin/Celite
Authors: Pannell Ralph , Angles-Cano Eduardo , Gurewich Victor 
Published: July 2018

SummaryA re-examination of the affinity of pro-urokinase (pro-UK), HMW and LMW-urokinase (UK) to fibrin/Celite was undertaken in order to explain how the chance purification of pro-UK from freshly voided urine by fibrin/Celite affinity chromatography may be reconciled with the subsequent observations that pro-UK failed to bind significantly to fibrin clots in plasma. A significant pH dependence of pro-UK binding to fibrin/Celite was found. Substantial binding of pro-UK (native or recombinant from E. coli), but not of the two-chains forms, was seen at about pH 6.5, which is in the normal pH range of pooled, freshly voided urine. By contrast, at pH 7.4 fibrin binding of pro-UK was much reduced, though it was still significantly greater than that of HMW or LMW-UK. This finding helps to explain the fibrin-binding of pro-UK in freshly voided urine but not in blood. In order to determine if this' pH dependence was the sole explanation for why pro-UK could not be isolated by this method from stored urine, the stability of pro-UK in urine was evaluated by incubating 125I-labeled pro-UK in urine: Incubation for up to 4 days (37° C) was not accompanied by any degradation of the single-chain pro-UK as evidenced by autoradiography under reducing conditions. It was concluded that the alkaline shift in pH which occurs in urine left standing, rather than the degradation of pro-UK, explained why freshly voided urine was found to be essential. Clot lysis studies at pH 6.5 and 7.4 showed no promotion of fibrinolysis at the pH which favored fibrin/Celite binding. Therefore, while the present study defines the conditions under which pro-UK may be purified from urine by fibrin/Celite chromatography, it provides no evidence that this binding phenomenon plays any role in fibrinolysis.
Synthetic RGDS-Containing Peptides of von Willebrand Factor Inhibit Platelet Adhesion to Collagen
Authors: Fressinaud Edith , Girma Jean Pierre , Sadler J Evan , Baumgartner Hans R , Meyer Dominique 
Published: July 2018

SummaryWe compared the effect of a synthetic dodecapeptide of residues 400-411 of the Γ chain of fibrinogen (Γ Fg 400-411) and of three synthetic peptides (15 to 18 aminoacids), of human von Willebrand Factor (vWF), containing the 1744-1747 Arg-Gly-Asp-Ser (RGDS) sequence, upon platelet adhesion to collagen in flowing blood. Both types of peptides are known to inhibit the binding of adhesive proteins to platelet membrane glycoprotein Ilb/IIIa (GPIIb/IIIa). Collagen was coated onto plastic cover slips and exposed in parallel-plate perfusion chambers to reconstituted human blood at various shear rates for 5 min at 37 °C. At a shear rate of 2,600 s−1, RGDS peptides inhibited platelet adhesion to collagen in a dose-dependent manner and appeared to be more potent inhibitors than the Γ Fg 400-411 on a molar basis. No synergetic effect between RGDS and Γ Fg 400-411 peptides was observed. These results suggest that the RGDS peptides affect adhesion by inhibiting the GPIIb/IIIa-vWF interaction and confirm the involvement of this platelet receptor in vWF-mediated platelet adhesion to collagen at high shear rate.
High Versus Ultra-high Purity Factor VIII Concentrate Therapy: Prospective Evaluation of Immunological and Clinical Parameters in HIV Seronegative and Seropositive Hemophiliacs
Authors: Varon D , Schulman S , Dardik R , Barzilai A , Bashari D , Martinowitz U 
Published: July 2018

SummaryThis study aimed at evaluation of the immunological status and the clinical course of both HIV seronegative and seropositive hemophiliacs treated with either an ultra-pure factor VIII product (UP-F VIII), or a high-purity F VIII (HP-F VIII) concentrate. Eighteen HIV seronegative patients were divided into two groups of therapy and their immune status was followed for 2 years. During the second year of the study 8 patients of the HP-F VIII and 6 from the UP-F VIII therapy groups were switched to the alternative F VIII concentrates. Eighteen asymptomatic HIV seropositive patients were also divided into therapy groups and their immune status and any development of HIV-related symptoms were followed for 4 years. Evaluation of the HIV seronegative patients during the first year did not reveal any differences between the groups in the CD4 or CD8 cell counts, in natural killer cell (NK) activity, or in the mitogenic responses of T lymphocytes to Phytohemagglutinin (PHA), and of B lymphocytes to Pokeweed mitogen (PWM). The switch of 8 patients from the HP-F VIII and 6 from the UP-F VIII groups to the alternative concentrate did not yield any changes in their immune profile during the second year of the study. The HIV seropositive groups differed in the initial CD4 count, with a lower CD4 count (193 ± 126 vs 437 ± 142) and a higher F VIII consumption (63,000 ± 17,000 vs 26,000 ± 10,000) in the UP-F VIII group. During four years of follow-up the annual decline of CD4 counts in the UP-F VIII group was 8 (5%) compared with 74 (17%) in the HP-F VIII group, with only the latter being significant. The decrease in delayed type hypersensitivity, was also significant in the HP-F VIII group alone. Cumulative HIV-related symptoms with an advancement from CDC category II to category IV were observed in 2 and 5 of the UP-F VIII and HP-F VIII treatment groups, respectively. Our data, taken separately or together with previously published studies, demonstrate the impact of purity of the F VIII concentrate on CD4 decline and possibly also on the clinical course in HIV seropositive hemophiliacs. In the seronegative group, we found no support for a beneficial effect on the immune system by switching to an ultra-pure F VIII concentrate.
Isolation and Characterization of Single-Chain Protein S
Authors: Meijer-Huizinga Fenny , Mertens Koen , van Mourik Jan A 
Published: July 2018

SummaryProtein S is a vitamin K-dependent cofactor of activated protein C in the proteolytic cleavage and concomitant inactivation of the coagulation factors Va and Villa. Protein S is sensitive to proteolysis by thrombin which reduces its functional activity. Uncontrolled proteolytic breakdown, leading to the generation of a two-chain molecule, is commonly encountered during the purification of both human and bovine protein S. In this study we demonstrate that human, single-chain, intact protein S can be isolated from plasma in a single step by affinity chromatography using a monoclonal antibody, CLB PS 52, directed to an epitope located within the thrombin-sensitive region of protein S. The product of purification was readily cleaved by thrombin after Arg49, resulting in a two-chain molecule which demonstrated a lower reactivity towards CLB-PS 52 than the parent single-chain protein. This study for the first time shows that intact protein S can be isolated directly from plasma using a monoclonal antibody selected for its ability to recognize uncleaved protein S.
Inhibition of Microarterial Thrombosis by Activated Protein C in a Rabbit Model
Authors: Arnljots Björn , Bergqvist David , Dahlbäck Björn 
Published: July 2018

SummaryProtein C is the key component in a natural anticoagulant pathway. After its activation by the thrombin-thrombomodulin complex, it degrades the activated forms of coagulation cofactors VIII and V, which leads to downregulation of the coagulation process. Due to its specific anticoagulant activity, activated protein C (APC) is potentially interesting as an antithrombotic agent. The effect of bovine activated protein C on thrombus formation and haemostasis was investigated in a rabbit model of microarterial thrombosis. Segments of both central ear arteries were prepared and blood-flow interrupted with double vascular clamps.Longitudinal arteriotomies (7 mm) and deep vessel wall trauma (5 mm) were performed, whereafter the arteriotomies were closed with running sutures. Five minutes prior to opening of the clamps (reperfusion), boluses of APC (0.8 mg/kg body weight) or vehicle alone were administered to two groups, each of 10 rabbits, in a blind random fashion. Vessel patency-rates were drastically improved by the administration of APC compared to vehicle. Correspondingly, thrombus weights were significantly lower in the APC group than in the control group. The activated partial thromboplastin time was prolonged to approximately twice the baseline throughout the 2 h observation interval in the APC group. Levels of circulating platelets were unaffected by the APC infusion, but the arteriotomy bleeding times were significantly longer in the APC group. In summary, activated protein C exerted powerful and long-acting antithrombotic effects in a microarterial model of thrombosis in rabbits.