bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Alternative Mechanisms of Collagen - Induced Platelet Activation by Using Monoclonal Antibodies to Glycoprotein IIb-IIIa and Fibrinogen
Authors: Connellan J M , Thurlow P J , Barlow Bernadette , Lowe Melinda , McKenzie I F C 
Published: July 2018

SummaryAnti-HuPl-ml (reactive with IIIa) and anti-C2G7 (reactive with the carboxyl terminal of the a chain of fibrinogen) were used to investigate platelet aggregation, fibrinogen binding and thromboxane synthesis induced by low dose collagen (LDC) or high dose collagen (HDC) in normal or aspirin treated platelets.Anti-HuPl-ml and anti-C2G7 inhibited LDC induced platelet aggregation almost completely whilst abolishing fibrinogen binding; thromboxane production although reduced, still occurred. Thus LDC activation was dependent on fibrinogen binding to Gp IIIa. Aggregation of platelets induced by HDC was inhibited with anti-C2G7 or anti-HuPl-ml by 15-35% in association with a modest reduction in thromboxane (TxB2) production (with anti-HuPl-ml) and total inhibition of fibrinogen binding. When anti-HuPl-ml was added to aspirin treated platelets, aggregation with HDC although substantially reduced was not totally abolished.Collagen appears to activate platelets in a dose related manner in which there are at least three possible mechanisms via: (i) GpIIb-IIIa and associated fibrinogen binding; (ii) prostaglandin pathway; (iii) an alternate pathway responsible for ∼20%-30% of platelet aggregation.
Experimental Studies on the Antithrombotic Action of a Highly Effective Synthetic Thrombin Inhibitor
Authors: Kaiser B , Markwardt F 
Published: July 2018

SummaryThe antithrombotic action of the highly effective synthetic thrombin inhibitor Nα-(2-naphthylsulfonylglycyl)-4-amidino-phenylalanine piperidide was studied in various models of experimental thrombosis in rats. Intravenous infusion of the thrombin inhibitor caused a dose-dependent inhibition or prevention of stasis-induced venous thrombosis, of arterial thrombosis after electrically-induced damage of the vessel wall and of thrombotic occlusion of an extracorporeal arterio-venous shunt.
Monoclonal Antibodies to Human 54,000 Molecular Weight Plasminogen Activator Inhibitor from Fibrosarcoma Cells - Inhibitor Neutralization and One-Step Affinity Purification
Authors: Nielsen L S , Andreasen P A , Grøndahi-Hansen J , Huang J Y , Kristensen P , Danø K 
Published: July 2018

SummaryMouse monoclonal antibodies were derived against a plasminogen activator inhibitor with a mol.wt. of ∼54,000 (54 K) from the human fibrosarcoma cell line HT-1080. Screening for hybrids producing antibodies directed against the inhibitor was performed with enzyme-linked immunosorbent assay and SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting. Four clones of hybridomas producing IgG1 antibodies were further characterized. The inhibitor was purified ∼50-fold to homogeneity from conditioned cell culture fluid with a yield of ∼85% by a one-step procedure using Sepharose-conjugated monoclonal antibody. In the 125I-fibrin plate assay one of the antibodies neutralized the effect of the inhibitor on urokinase-type plasminogen activator. Two of the antibodies bound complexes between urokinase-type plasminogen activator and inhibitor while the remaining two antibodies did not. The antibodies could be used for immunocytochemical localization of the inhibitor in HT-1080 cells. All four antibodies cross-reacted with a plasminogen activator inhibitor derived from cultured human umbilical cord endothelial cells.
The Systemic Fibrinolytic Effect of BRL 26921 During the Treatment of Acute Peripheral Arterial Occlusions
Authors: Earnshaw J J , Westby J C , Makin G S , Hopkinson B R 
Published: July 2018

SummaryBRL 26921 is a new acylated streptokinase-plasminogen complex which may have a more specific local thrombolytic effect than streptokinase or urokinase. 34 patients with acute peripheral arterial occlusions were given eight hourly bolus injections of 5 mg BRL 26921 for up to 72 h. Systemic fibrinolysis was observed in all patients yet in only 24% was the occluding thrombus lysed. 44% of the patients had haemorrhagic complications and 24% suffered further thrombotic events during or soon after treatment. There was no correlation between the degree of systemic fibrinolysis produced and dissolution of the thrombi. The degree of systemic fibrinolysis did not affect the complication rate. There is no evidence from this study that BRL 26921 has a specific local thrombolytic effect.
Further Studies on Aggregation of Platelet-Type von Willebrand’s Disease Platelets by Human von Willebrand Factor
Authors: Takahashi H , Tatewaki W , Hanano M , Nagayama R , Shibata A 
Published: July 2018

SummaryPlatelet-type von Willebrand’s disease (vWD) is a bleeding disorder characterized by a heightened interaction between platelets and von Willebrand factor (vWF) as the result of an intrinsic platelet abnormality (probably in GPIb). Platelet aggregability was nearly normal in response to thrombin, wheat germ agglutinin and Ricinus communis agglutinin in this disorder. Unmodified platelets showed no aggregation upon the addition of peanut agglutinin. Partially purified human vWF induced little aggregation of washed patient platelets, but the aggregation was greatly enhanced in the presence of plasma devoid of vWF. Monoclonal antibodies directed against GPIb and GPIIb/IIIa as well as EDTA completely inhibited vWF-induced aggregation. These results indicate that human vWF induces aggregation of platelet-type vWD platelets in the presence of divalent cations and some plasma cofactor(s), and that both GPIb and GPIIb/IIIa are involved in this aggregation.
Monoclonal Antibodies Against Human High Molecular Weight Urinary Urokinase: Application for Affinity Purification of Urinary Prourokinase
Authors: Wojta J , Kirchheimer J C , Turcu Liselotte , Christ G , Binder B R 
Published: July 2018

SummaryMonoclonal antibodies against urinary urokinase were obtained by immunizing mice with purified human high molecular weight urokinase. Five antibodies were selected and denominated MPW1UK, MPW2UK, MPW3UK, MPW4UK, and MPW5UK, respectively. All selected antibodies reacted with high and low molecular weight urokinase. Cleavage of the low molecular weight paranitroanilide substrate pyro-Glu-Gly-Arg-pNA by urokinase was not inhibited by the antibodies and only one antibody (MPW5UK) inhibited plasminogen activation by urokinase. The ability of MPW5UK to bind to coated urokinase was 100-fold higher than that of the other antibodies. MPW5UK was used to prepare an immunosorbent for the purification of urokinase antigen from freshly voided crude urine. One-chain prourokinase was separated from two-chain urokinase by chromatography of the urokinase antigen containing mixture on agmatine Sepharose. As judged by SDS gel electrophoresis one-chain prourokinase as well as two-chain urokinase were purified to apparent homogeneity by this two-step procedure; the yields were 18% and 47% for single-chain prourokinase and two-chain urokinase, respectively, as calculated from total urokinase antigen contained in the starting material.
Inhibition of Tissue-Type Plasminogen Activator in Plasma of Women Using Oral Contraceptives and in Normal Women During a Menstrual Cycle
Authors: Jespersen J , Kluft C 
Published: July 2018

SummaryTissue-type plasminogen activator (t-PA) inhibition in plasma was assessed in 15 normal women and in 10 women using oral contraceptives (OC) containing 30 μg ethinyl oestradiol and 150 μg levo-norgestrel. The levels of t-PA inhibition were significantly lower in the OC group with marked fluctuations related to the hormone cycle. Normal women had only minor fluctuations.
A Pasteurised Concentrate of Human Plasma Factor XIII for Therapeutic Use
Authors: Winkelman L , Sims G E , Haddon M E , Evans D R , Smith J K 
Published: July 2018

SummaryA therapeutic concentrate of factor XIII containing both A and B sub-units has been prepared from 300 kg pools of human plasma. The process starts from a cold-ethanol fraction from cryoprecipitate supernatant and therefore does not interfere with the recovery of other clinically valuable plasma proteins. Factor XIII is purified approximately 600-fold from plasma by precipitation with sodium citrate and by the removal of fibrinogen by brief heating. The product has been pasteurised in sorbitol solution to inactivate blood-borne viruses, ultrafiltered to remove sorbitol, adsorbed with bentonite and freeze-dried in a formulation meeting requirements for intravenous injection.
Interaction of Vasopressin with Human Blood Platelets: Dependency on Mg2+
Authors: Roos Isabella , Ferracin Fabrizia , Pletscher Alfred 
Published: July 2018

SummaryArginine-vasopressin (AVP) in the presence of Mg2+ but not in the absence of bivalent cations led to accumulation of [32P]-phosphatidic acid ([32P]-PA) in human blood platelets. Mg2+ also enhanced the specific binding of [3H]-AVP to intact platelets. The concentrations of the cation which enabled AVP to cause half maximal rise of [32P]-PA and those inducing half maximal [3H]-AVP-binding were of the same order. It is concluded that the stimulation of phosphatidyl inositide breakdown by AVP in presence of Mg2+ is at least partially due to a Mg2+-induced enhancement of specific AVP-binding to the platelet membranes.
Characterization of Four Monoclonal Antibodies to Factor VIII Coagulant Protein and Their Use in Immunopurification of Factor VIII
Authors: Croissant Marie-Pascale , vande Pol Hendrik , Lee Helen H , Allain Jean-Pierre 
Published: July 2018

SummaryFour monoclonal anti-VIII: C antibodies were obtained from the fusion of the splenocytes of one B alb/C mouse with a specific activity ranging from 2.3 to 45,000 U/mg when purified from ascitic fluid. Only one antibody was able to inhibit completely Factor VIII: C in normal plasma. The four antibodies could bind Factor VIII: CAg in plasma and commercial concentrate both in liquid and solid phase, and were suitable for immunopurification of Factor VIII :C.Three antibodies competed with polyclonal anti-VIII: CAg Fab′ in a liquid phase IRMA, and all of them were able to displace their own binding to Factor VIII: CAg. Competition studies between monoclonal antibodies for the binding to Factor VIII: CAg were performed and showed the recognition of different epitopes and various functional impact. These studies indicate that at least one antibody, with the lowest anti-VIII:C titer clearly recognizes a different epitope of VIII: C than those recognized by the others. Affinity constants ranged from 109 to 1010 l/mole.
Prolonged Bleeding Time, Reduced Platelet Aggregation, Altered PAF-Acether Sensitivity and Increased Platelet Mass Are a Trait of Asthma and Hay Fever
Authors: Szczeklik A , Milner P C , Birch J , Watkins J , Martin J F 
Published: July 2018

SummaryIn a case control study 31 asymptomatic patients with asthma and/or hay fever and 31 normal controls had their bleeding time measured using the Simplate II device and venostasis. Mean bleeding time in the atopic group (527 s) was significantly prolonged compared to the controls (393 s) (p <0.0005). Platelet aggregation to collagen and ADP (but not to PAF-acether) was significantly depressed in the atopies. Mean circulating platelet mass was significantly greater in atopies than in the controls (p = 0.006). Stepwise multiple regression analysis showed that within the control group bleeding time was best predicted by platelet mass (p = 0.007). No such relationship was found in the atopies. However stepwise multiple regression analysis showed that bleeding time in the atopies (but not in the controls) was best predicted by PAF-acether induced platelet aggregability (p <0.05). In neither group was bleeding time related to collagen induced platelet thromboxane B2 production.It is hypothesised that in respiratory atopy the depressed aggregatory function of platelets is not compensated for sufficiently by an increase in platelet mass, leading to prolongation of the bleeding time. This haemostatic imbalance, whose cause remains to be established, appears to constitute a trait of atopy.
Role of Red Blood Cells in the Early Stages of Platelet Activation by Collagen
Authors: Teresa Santos M , Vallés Juana , Aznar Justo , Luis Pérez-Requejo J 
Published: July 2018

SummaryRed blood cells (RBC) increase the proaggregatory capacity of a cell-free supernatant obtained by stimulating platelet-rich plasma (PRP) samples with collagen (1 μg/ml) as measured by the BASIC wave; this effect increases with the number of RBC and is proportionally greater with a lower number of platelets or when lower collagen concentrations are used.Aspirin (ASA) modifies the RBC behaviour in relation to their platelet-collagen interaction. This is demonstrated by the fact that when PRP and RBC obtained from the same subjects before and two hours after the ingestion of ASA (0.5 g) were mixed, it was found that non-AS A-RBC stimulate ASA-PRP, probably through a platelet cyclooxygenase independent pathway; ASA-RBC, however, stimulate non-ASA-PRP, but not ASA-PRP, which suggests that they may need an active platelet cyclooxygenase system for their action. This effect of ASA on RBC is not transient and was also observable 48 h after ASA ingestion. In addition, it was found that ASA-RBC greatly increase the activation of a mixture containing a small proportion of non-ASA-PRP in ASA-PRP, a situation that is expected to be encountered “in vivo” after ASA treatment. This effect of ASA-RBC on platelet activation may help to explain the sometimes contradictory clinical effect of aspirin as an antithrombotic drug.
Measurement of Urokinase-Type Plasminogen Activator (u-PA) with an Enzyme-Linked Immunosorbent Assay (ELISA) Based on Three Murine Monoclonal Antibodies
Authors: Darras V , Thienpont M , Stump D C , Collen D 
Published: July 2018

SummaryAn enzyme-linked immunosorbent assay (ELISA) for the measurement of urokinase-type plasminogen activator (u-PA) was developed. Three murine monoclonal antibodies to single chain urokinase-type plasminogen activator (scu-PA) were isolated and shown to react with non-overlapping epitopes in scu-PA. Two of the three antibodies were coated onto microtiter plates and bound u-PA was quantitated with the third antibody conjugated to horseradish peroxidase. The assay was equally sensitive to Mr 54,000 u-PA in the single chain or two-chain form but did not respond to Mr 33,000 urokinase. The lower limit of sensitivity of the assay was 0.1 ng/ml in buffer and 1 ng/ml in plasma. Coefficients of variation of the assay at physiological levels of u-PA were 6.5 percent within assays and 13 percent between assays. The level of u-PA in normal resting plasma was 1.9 ± 0.66 ng/ml (mean ± SD, n = 54). The assay can be performed within one working day and provides an efficient, reproducible, and stable means for the measurement of u-PA in biological fluids. As such it may facilitate physiological and pharmacological studies of urokinase-type plasminogen activators in man.
T-Cell Alterations in Hemophiliacs Treated with Commercial Clotting Factor Concentrates
Authors: Lechner K , Niessner H , Bettelheim P , Deutsch E , Fasching I , Fuhrmann M , Hinterberger W , Korninger C , Neumann E , Liszka K , Knapp W , Mayr W R , Stingl G , Zeitlhuber U 
Published: July 2018

SummaryVarious immunological parameters were determined in 46 patients with severe hemophilia A and in 9 patients with severe hemophilia B. All patients were treated over many years with commercial factor VIII or IX concentrates. Patients with severe classic hemophilia had a significantly reduced relative and absolute number of T-helper cells and a significantly increased relative and absolute number of T-suppressor cells. About half of these patients had an inverse T-helper/suppressor cell ratio. Patients with moderate hemophilia A and severe hemophilia B did not show these abnormalities. Hemophiliacs with an inverse ratio had a significantly higher concentration of serum total protein, IgG and IgM. No relationship between the amount of factor VIII concentrate administered, the HLA-type of the patient, the presence or absence of CMV-antibodies, hepatitis markers, thrombocytopenia and abnormal liver function tests to the T-cell abnormalities could be established. Lymphadenopathy was frequently associated with an inverse ratio. Indirect evidence suggests that the alterations of the immune system began in 1979/80.
Mechanisms of Vascular Damage in Gout and Oxalosis: Crystal Induced, Granulocyte Mediated, Endothelial Injury
Authors: Boogaerts M A , Hammerschmidt D E , Roelant C , Verwilghen R L , Jacob H S 
Published: July 2018

SummaryImmune triggered granulocyte (PMN)-endothelial interactions have been implicated in the pathogenesis of vascular diseases. While hyperuricemia and gout are associated with an increased risk of atherogenesis, we studied the modulation by mono- sodiumurate (MSU) crystals of PMN-endothelial interactions in vitro. The relationship between calciumoxalate (COX) crystals - implicated in the vasculitis of primary oxalosis - and immunologically mediated endothelial injury was also explored.Both MSU- and COX-crystals activate complement (C), as illustrated by the finding of strong PMN aggregating activity and large amounts of C3a and C5a-anaphylatoxin in MSU- and COX- crystal incubated sera.MSU- and COX-crystal treated sera stimulate PMN to adhere to and induce significant 51Cr-release from endothelial cells in vitro. Platelets significantly increase crystal-triggered PMN endothelial cell adherence and 51Cr-release. This platelet augmenting effect depends on the release of platelet constituents (e. g. serotonin).Microcrystalline material present in vessel walls, thus may cause C-activation and may trigger PMN and platelets to damage endothelium in vitro and in vivo. These findings may have relevance to the understanding of the accelerated atherogenesis of hyperuricemia and the fulminant vasculitis of oxalosis or ethylene glycol poisoning.
Individual Levels of Plasma α2-Antiplasmin and α2 Macroglobulin During the Normal Menstrual Cycle and in Women on Oral Contraceptives Low in Oestrogen
Authors: Jespersen Jørgen , Sidelmann Johannes 
Published: July 2018

SummaryDeterminations of α2-antiplasmin and α2-macroglobulin were made in plasma samples collected during one normal or hormone induced cycle in 15 normal women and 11 women using oral contraceptives containing 30 μg ethinyl oestradiol and 150 pg levo-norgestrel. The immediate plasmin inhibition test for determination of α2-antiplasmin was modified for application on a centrifugal analyser using the chromogenic peptide substrate Chromozym PL®. α2-Macroglobulin concentration was determined by radial-immunodiffusion. There were no differences between the two groups in the mean concentrations of α2- antiplasmin and α2-macroglobulin, but during the cycle a slight, and statistically significant fall occurred in the α2-antiplasmin concentration in both groups, while the fluctuations of α2- macroglobulin were small and insignificant. Distinctly individual levels of both inhibitors were found to exist. The variations in these during the periods of the cycle fluctuated within a much narrower range than the variation of the total average. The results stress the importance of determining the fluctuations in individual levels in longitudinal studies. These findings exclude variations in the concentrations of these inhibitors as possible sources of a change in the antithrombotic potential caused by oral contraceptives.
Factor XIII Levels in Five Families of Patients with Inherited Factor XIII Deficiency: Support for an Autosomal Recessive Inheritance
Authors: Fear J D , Miloszewski K J A , Losowsky M S 
Published: July 2018

SummaryUsing quantitative methods, f.XIII activity and levels of subunits a and b have been measured in 5 families of 6 patients with inherited XIII deficiency, including 2 children of a XIII deficient male. The parents, as a group, and the children, individually, have low XIII activity and low levels of subunit A when compared to controls. These findings provide further support for an autosomal inheritance of f.XIII deficiency. The measurements, however, did not allow confident selection of individual heterozygotes as has been previously suggested and an explanation of this finding is offered.
Measurement of Crosslinked Fibrin Degradation Products – An Immunoassay Using Monoclonal Antibodies
Authors: Elms M J , Bunce I H , Bundesen P G , Rylatt D B , Webber A J , Masci P P , Whitaker A N 
Published: July 2018

SummaryWe have prepared a monoclonal antibody which recognises an antigenic determinant on D dimer, a specific fragment resulting from the degradation of crosslinked fibrin. This antibody has been used in the development of an enzyme-linked immunoassay for D dimer and related degradation products containing crosslinked gamma-gamma chains, to provide a simple assay of circulating crosslinked fibrin degradation products suitable for clinical use. Since these crosslinked fibrin degradation products are characteristic of fibrinolysis, as distinct from fibrinogenolysis, their measurement should aid in the diagnosis, evaluation and monitoring of thrombotic and thrombolytic states. In preliminary studies, low concentrations of crosslinked fibrin derivatives were detected in normal sera. High levels were found in 30/30 patients with disseminated intravascular coagulation .and in the majority of patients having deep venous thrombosis or pulmonary embolism.
Lipid Class Composition and Heparin Sensitivity in the Activated Partial Thromboplastin Time
Authors: Stevenson K J , Easton Ann C , Thomson Jean M , Poller L 
Published: July 2018

SummaryIn an APTT reagent, prepared from purified lipids, the role of phosphatidyl serine (PS) in determining the sensitivity of the APTT test system to measurement of the effect of heparin in plasma has been evaluated. As the concentration of PS decreases sensitivity to heparin increases but procoagulant activity decreases. Dilution of the test liposome over a wide range (1 g/1 to 30 mg/1) had a minimal effect on the clotting time. At levels below 30 mg/1, however, the amount of total lipid appeared to be rate limiting; a loss of procoagulant activity being paralleled by an increase in heparin sensitivity. Phosphatidyl inositol (PI) was not a satisfactory substitute for PS in the APTT method studied. The degree of unsaturation of test liposomes appeared to have no effect on either procoagulant activity or sensitivity to heparin at the lipid concentration employed.In the light of these findings, a more critical appraisal of the phospholipid components of APTT reagents should facilitate the development of more reliable reagents for heparin control. A further benefit of this type of approach should be a reduction in the acknowledged wide variations in sensitivity to heparin which exist between available APTT reagents.