bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potentiation by Lys-Plasminogen of Clot Lysis by Single or Two Chain Urokinase-Type Plasminogen Activator or Tissue-Type Plasminogen Activator
Authors: Watahiki Y , Scully M F , Ellis V , Kakkar V V 
Published: July 2018

SummaryStudy has been made of the influence of addition of human NH2 terminal glutamic acid plasminogen (Glu-Plg) or human NH2 terminal lysine plasminogen (Lys-Plg) to normal citrated plasma upon the rate of lysis of fully crosslinked plasma clots in the presence of single or two chain urokinase type plasminogen activator (scu-PA/tcu-PA) or tissue plasminogen activator (t-PA). The Specificity of any thrombolytic property was evaluated by measurement of plasma fibrinogen levels. Lys-plgadded to a concentration of 20% of normal plasma plasminogen caused 5 to 6 fold increase in the extent of lysis observed at 6 hours by 100 units/ml of scu-PA and with a small increase in fibrinogenolysis. Glu-Plg added at 20% of normal level had no influence on thrombolysis but at 50% of normal caused increased thrombolysis with rapid depletion of plasma fibrinogen. An apparently synergistic effect of addition of tcu-PA on scu-PA activity was increased by addition of plasminogen (e.g. addition of 20% Lys-Plg increased the lysis rate 4 to 5 fold over the first hour equivalent to an increase of potency of approximately three to four fold). Addition of plasminogen up to double the normal plasma concentration was observed to have no influence on clot lysis in the presence of t-PA. Plasminogen potentiated the rate of lysis by scu-Pr/t-PA synergic mixtures with an approximately 1.5 to 1.9 fold increase in potency. Potentiation occurred without increase in the depletion of plasma fibrinogen. It is concluded that Lys-Plg may be a suitable agent to improve the thrombolytic efficacy of scu-PA, scu-PA/tcu-PA or scu-PA/t-PA therapeutic regimen.
Isolation of Multiple Types of Plasminogen Activator Inhibitors from Vascular Smooth Muscle Cells
Authors: Laug Walter E , Aebersold Ruedi , Jong Ambrose , Rideout Willian , Bergman Barbara L , Baker Joffre 
Published: July 2018

SummaryLarge arteries have a natural resistance to tumor cell invasion thought to be due to the production of protease inhibitors. Vascular smooth muscle cells (VSMC) representing the major cellular part of arteries were isolated from human aortas and grown in tissue culture. These cells were found to produce large amounts of inhibitors of plasminogen activators (PA). Fractionation of VSMC-conditioned medium by heparin-affigel chromatography separated three immunologically and functionally distinct PA inhibitors (PAI), namely PAI-1, PAI-2 and protease-nexin I. The three inhibitors were characterized by functional assays and immunoblotting. PA inhibitor 2 (PAI-2) had little affinity for heparin, whereas PA inhibitor 1 (PAI-l) bound to heparin and was eluted from the column at NaCl concentrations of 0. 1 to 0.35 M. Protease-nexin I, eluted at NaCl concentrations of 0.5 M and higher. Most of the PAI-1 was present in the latent, inactive form. PAI-1 was further purified by ion exchange chromatography on a Mono-Q column. Partial sequencing of the purified PAI-1 confirmed its nature by matching completely with the sequence deduced from the cDNA nucleotide sequence of endothelial cell PAI-1. Thus, human VSMC produce all three presently known PAI and these can be separated in a single heparin affinity purification step.
Ridogrel, a Combined Thromboxane Synthase Inhibitor and Receptor Blocker, Decreases Elevated Plasma β-Thromboglobulin Levels in Patients with Documented Peripheral Arterial Disease
Authors: Hoet B , Arnout J , Van Geet C , Deckmyn H , Verhaeghe R , Vermylen J 
Published: July 2018

SummaryThe combination of thromboxane synthase inhibition with thromboxane receptor antagonism has been shown to result in a strong inhibition of platelet aggregation and a prolongation of the bleeding time (Gresele et al., J. Clin Invest 1987;80: 1435–45).Ridogrel is a single molecule that efficiently achieves both inhibitions in human volunteers. The present study was performed in patients with obstructive peripheral arterial disease and elevated plasma β-thromboglobulin levels. Patients were treated with either 2 × 300 mg ridogrel or 2 × 300 mg placebo per day for 2½ days, according to a double blind randomised parallel design. Plasma β-thromboglobulin decreased significantly throughout active treatment starting within 2 h after administration; serum and urinary immunoreactive TxB2 levels and urinary 11-dehydro- TxB2 excretion were significantly lower and serum PGE2 and 6-keto-PcF1α levels significantly higher with ridogrel; no changes were observed in the placebo-treated group.In conclusion this study demonstrates a reduction of platelet activation in vivo by ridogrel.
Effect of Ridogrel on Vascular Contractions Gaused by Vasoactive Substances Released during Platelet Activation
Authors: Janssens W J , Cools F J S , Hoskens L A M , Van Nueten J M 
Published: July 2018

SummaryRidogrel (6.3 × 10−6 to 10−4 M) inhibited contractions of isolated rat caudal arteries and rabbit femoral arteries caused by U-46619. The slope of an Arunlakshana-Schild plot (pA2-value: 3.4 × 10−6 M) on the caudal artery was slightly higher than one (1.14). This effect was maximal within}D min of incubation of the blood vessel with the compound and easily reversible. Ridogrel antagonised contractions of isolated rabbit femoral arteries caused by prostaglandin Fzo2α in the same concentration range. Ridogrel also inhibited contractions induced by aggregating rat platelets on isolated rat caudal arteries (itt the presence of ketanserin 4 × 10−7 M) and on isolated rabbit pulmonary and femoral arteries (in the absence of ketanserin). Ridogrel had no effect on Ca2+-induced contractions in depolarised isolated rabbit femoral arteries, and at 10−4 M antagonised serotonin-induced contractions in this blood vessel. Its effect on serotonin-induced contractions was statistically significant but very small on isolated rat caudal arteries. These observations indicate that ridogrel is an antagonist of prostaglandin endoperoxide/thromboxane A2 and prostaglandin F2α raCeptors on vascular smooth muscle.
Bispecific Monoclonal Antibodies Produced by Somatic Cell Fusion Increase the Potency of Tissue Plasminogen Activator
Authors: Branscomb Elizabeth E , Runge Marschall S , Savard Christopher E , Adams Keith M , Matsueda Gary R , Haber Edgar 
Published: July 2018

SummaryBispecific monoclonal antibodies that bind simultaneously to human fibrin and tissue plasminogen activator (tPA) enhance the fibrinolytic potency of tPA. Two bispecific antibodies (F36.23 and F32.1) were generated by somatic cell fusion. Antibody F36.23 derives its tPA binding from monoclonal anti-tPA antibody TCL8 and its fibrin binding from monoclonal antifibrin antibody 59D8. After purification from cell supernatants and ascites by two steps of affinity chromatography, hybrid-hybridoma bispecific antibody F36.23 simultaneously bound tPA and fibrin in solution and in solid-phase assays. In an assay for the lysis of human fibrin monomer, F36.23 increased the fibrinolytic potency of tPA by 5 to 10 fold, regardless of whether the bispecific antibody had been combined with the tPA before or during the assay. Bispecific F36.23 F(ab′)2 also bound tPA and fibrin simultaneously, and the enhancement in fibrinolysis in the presence of F36.23 F(ab′)2 was identical to that in the presence of intact F36.23. The second bispecific antibody, F32.1, was produced by an alternative strategy that has a wider potential for applicaton in other systems. Hybridoma bispecific antibody F32.1 was derived from the fusion of immune splenocytes (in mice immunized with a synthetic oligopeptide representing the amino terminus of the α-chain of human fibrin) with the anti-tPA cell line TCL8. The properties of hybridoma bispecific antibody F32.1 and its F(ab′)2 were indistinguishable from those of hybrid-hybridoma bispecific antibody F36.23 in solid-phase binding assays and in assays of fibrinolysis. Bispecific antibodies produced by somatic cell fusion, particularly in the form of F(ab′)2, may have potential for use in clinical thrombolysis.
Plasmin inactivation in Plasma
Authors: Haselager E. M , Goote Th. M , Vreeken J 
Published: July 2018

SummaryInhibition and inactivation of plasmin is ascribed to α2-macroglobulin, α1-antitrypsin and c1-esterase inhibitor. In an “overall” inactivation test of plasmin in plasma, which comes perhaps closest to rapid inactivation of plasmin in the circulating blood, we only found a correlation between the immunological concentration of α2-macroglobulin and the plasmin-inac-tivating capacity of the plasma, but no correlation with the immunological concentration of the other inhibitors mentioned. Therefore, α2-macroglobulin seems to be the most important plasmin inhibitor in relation to thrombosis.
Monoclonal Purified F VIII for Continuous Infusion: Stability, Microbiological Safety and Clinical Experience
Authors: Schulman S , Varon D , Keller N , Gitel S , Martinowitz U 
Published: July 2018

SummaryReplacement therapy for patients with hemophilia A postoperatively or for major hemorrhage, administered as a continuous infusion, is efficient and reduces the requirement for factor VIII (F VIII). The convenience of the method is increased by using a minipump and not diluting the concentrate further after reconstitution. A monoclonally purified F VIII concentrate (Monoclate-P®), was evaluated for its stability after reconstitution in different infusion systems, for its microbiological safety as well as clinical safety and efficacy in continuous infusion. The F VIII activity was unaffected by 2 of the 3 infusion systems at room temperature during 15 days, whereas in the third (CADD®-1) it decreased below 80% of initial value after 3-7 days. Addition of heparin (1 U/ml) or low molecular weight heparin (1 anti-Xa U/ml), which are used to prevent thrombophlebitis at the site of infusion, did not affect the stability. Nine out of 9 samples taken from the infusion systems after 3 days and again after 7 days were sterile. After inoculation with Staphylococcus aureus or Escherichia coli the bacterial growth in samples of the reconstitued concentrate was not different from that in lidocain in saline or heparin in saline. F VIII was given in continuous infusion with a minipump (Infu-Med™) to 12 patients undergoing major surgery and 8 patients with major hemorrhage for a total of 157 days. A progressive decrease of the clearance was seen during the first 5 days of infusion from 3.0 to 1.7 ml/kg/h. Hemostasis was effectively achieved, and no infectious complications were registered. The administration of monoclonally purified F VIII with a minipump is safe, efficient and convenient and reduces the consumption of F VIII when high doses are needed. Some patients can be discharged earlier and admission to the hospital may even be unnecessary, since high and steady F VIII levels can be maintained.
Thromboplastin Related Differences in the Determination of International Normalised Ratio: A Cause for Concern?
Authors: Kitchen S , Walker I D , Woods T A L , Preston F E 
Published: July 2018

SummaryWhen the International Normalised Ratio (INR) is used for control of oral anticoagulant therapy the same result should be obtained irrespective of the laboratory reagent used. However, in the UK National External Quality Assessment Scheme (NEQAS) for Blood Coagulation INRs determined using different reagents have been significantly different.For 18 NEQAS samples Manchester Reagent (MR) was associated with significantly lower INRs than those obtained using Diagen Activated (DA, p = 0.0004) or Instrumentation Laboratory PT-Fib HS (IL, p = 0.0001). Mean INRs for this group were 3.15, 3.61, and 3.65 for MR, DA, and IL respectively. For 61 fresh samples from warfarin-ised patients with INRs of greater than 3.0 the relationship between thromboplastins in respect of INR was similar to that observed for NEQAS data. Thus INRs obtained with MR were significantly lower than with DA or IL (p <0.0001). Mean INRs for this group were 4.01, 4.40, and 4.59 for MR, DA, and IL respectively.We conclude that the differences between INRs measured with the thromboplastins studied here are sufficiently great to influence patient management through warfarin dosage schedules, particularly in the upper therapeutic range of INR. There is clearly a need to address the issues responsible for the observed discrepancies.
Relation between Plasminogen Activator Inhibitor-1 and Hepatic Enzyme Concentrations in Hyperlipidemic Patients
Authors: Bruckert E , Ankri A , Glral P , Turpin G 
Published: July 2018

SummaryPlasminogen activator inhibitor type-1 (PAI-1) is a key determinant of the fibrinolytic capacity. Its activity correlates with most of the characteristic features of insulin resistance syndrome, i. e. obesity, high blood pressure and hyperlipidemia.We measured plasma PAI-1 antigen levels in 131 asymptomatic men (aged 44.2 ± 11 years) who had been referred for hyperlipidemia. Those taking medication and those with a secondary hyperlipidemia were excluded.We confirmed the correlation between PAI-1 levels and the following variables: body mass index, blood pressure, triglyceride concentration, and blood glucose and insulin levels before and after an oral glucose tolerance test. We also found a significant and independent correlation between PAI-1 and the concentration of the hepatic enzymes glutamyl transferase, alanine aminotransferase and aspartate aminotransferase.Mild liver abnormalities (presumably steatosis) may thus be one of the factors accounting for high plasma PAI-1 levels in hyperlipidemic patients.
Proteolytic Inhibitors, Contact and Other Variables in the Release Reaction of Human Platelets
Authors: Zucker Marjorie B. 
Published: July 2018

SummaryPlatelet-rich plasma (PRP) containing platelets labelled with 14C-serotonin was used to characterize the release reaction. Heparin promotes release, and the reduced release response to epinephrine observed in heparinized compared to citrated PRP is probably due to the earlier reaction. The release reaction can occur in citrated PRP at pH 7.0, is marked between pH 7.2 and 7.6, and decreases above pH 8.0. It is retained better when PRP is stored below pH 7.7. Adenosine, prostaglandin E1, and theophylline inhibit both aggregation and release, probably because they elevate cyclic AMP. D- and L-tosyl-phenylalanine chloromethylketone (TPCK) also inhibit both aggregation and release at a concentration of 0.1 mM whereas 0.1 mM D- and l-L-chloro-2-tosylamido-7-amino-2-heptanone (TLCK) and 5 mM diisopropylfluoro-phosphate (DFP), like aspirin, inhibit only release. Colchicine (0.1 mM) alters platelet shape but does not affect release or aggregation. Centrifugation of PRP at 37° C causes release which responds to inhibitors and pH changes in a manner similar to release induced by aggregation with ADP or epinephrine. Release occurs in thromb-asthenic platelets centrifuged at 37° C and is increased by epinephrine. Release of ATP and ADP correlates significantly with release of 14C-serotonin. Thrombin plus CaCl2 causes release of β-glucuronidase but not of zinc.
Kymographic Recording of Clot Retraction: Effects of Papaverine. Theophylline and Cytochalasin B
Authors: Majno G , Bouvier C.A , Gabbiani G , Ryan G.B , Statkov P 
Published: July 2018

SummaryClot retraction was studied by setting up ribbon-shaped clots in a pharmacological bath and recording the progress of contraction on a kymograph. Drugs could be added to the bath or washed out at any stage. Papaverine, theophylline and cytochalasin B each reversed the upward course of the kymograph tracing ; contraction began again when the drugs were washed from the bath. This phenomenon resembles the behaviour of smooth muscle under similar circumstances.
Blood Coagulation and Fibrinolysis in a Random Sample of 788 Men 54 Years Old
Authors: Korsan-Bengtsen Kristoffer , Wilhelmsen Lars , Tibblin Gösta 
Published: July 2018

SummaryIn a population of 788 men 54 years of age plasma clotting times, factor II-VII-X activity, factor VIII, fibrinogen, fibrinolytic activity and plasminogen have been compared to anthropomorphic variables, blood lipids, blood sugar, blood pressure, heart rate, lung function and smoking.It was found by multiple regression analyses that fibrinogen, plasminogen and factor II-VII-X activity were correlated to serum cholesterol, and secondary to systolic blood pressure, heart rate and blood sugar.Independent of these correlations, fibrinogen, plasminogen and factor II-VII-X activity were also negatively correlated to FEV1 and VC which are measures of lung function.Smokers have a higher fibrinogen level than non smokers and this is not due to the decreased lung function in smokers. PTT (partial thromboplastin time) carried out in silicone tubes is correlated to serum cholesterol.There is a negative correlation between fibrinolytic activity and weight, subscapular and thorax skinfolds, chest and waist chcumference indicating that obese subjects have a low fibrinolytic activity. There is also a negative correlation between fibrinolytic activity and serum triglycerides but this is insignificant when the effect of obesity is taken into account.
Influence of Platelet Count on Haemostatic Plug Formation and Plug Stability
Authors: Bergqvist D , Arfors K.-E 
Published: July 2018

SummaryThe initial haemostatic process in thrombocytopenic animals after transection of arterioles and venules was investigated in a rabbit mesenteric preparation. Graded thrombocytopenia with a bone marrow suppressant (busulphan) and anti-platelet serum gave comparable results. With decreasing platelet counts there was progressive prolongation in haemostatic plug formation time, and a significant non-linear relation between platelet count and haemostatic plug formation time. Haemostatic plugs formed under thrombocytopenic conditions were more stable than normal. The difference in stability normally seen between plugs in arterioles and venules disappeared with decreasing platelet counts. The relationship between venular and arteriolar haemostatic plug formation time was also reduced with decreasing platelet counts.
Oral Anticoagulant Therapy and its Control: An International Survey
Authors: Lam-Po-Tang P. R. L. C , Poller L 
Published: July 2018

SummaryA survey for the International Study Group for Anticoagulant Control has been conducted in which a questionnaire was sent to members in 39 countries. Information based on 37 replies obtained indicated that the most widely used test in oral anticoagulant therapy is the Quick one stage prothrombin estimation. There is a great diversity in the method of reporting prothrombin time results. Percentage activity of normal on the basis of saline dilution curves is the most popular. Only six countries have national or regional systems for anticoagulant control.Recommendations for the therapeutic range of dosage vary widely. The upper limit in one country may be the lower limit in another. In many centres doses of anticoagulant drugs are advocated which elsewhere are considered either inadequate anticoagulation or dangerous overdosage. The variation of therapeutic range may still be considerable even when a standard thromboplastin is available.Data collected from the survey indicates the need for urgent measures to provide a uniform basis of laboratory control of clinical dosage of anticoagulant drugs. Until such measures are implemented it is meaningless to try to compare the efficacy of oral anticoagulant therapy from country to country or even to attempt multicentre trials within national boundaries.
An International Collaborative Study to Investigate Standardisation of Hirudin Potency
Authors: Longstaff Colin , Wong Man-Yu , Gaffney Patrick J 
Published: July 2018

SummaryAn international collaborative study has been carried out to investigate the reproducibility of hirudin assays in 13 laboratories using four recombinant hirudins and one natural, sulphated product. A simple assay procedure was proposed involving the titration of α-thrombin with inhibitor and measurement of residual activity using a chromogenic substrate. A standard α-thrombin preparation was supplied to ensure that this reagent was of uniform quality throughout the study. The method appeared to present no difficulties and laboratories reported similar potencies for the 5 hirudin samples, in line with expected values. This gave 200–222 Thrombin Inhibitory Units/ampoule (TIU/ampoule) of lyophilised hirudin, with geometric coefficient of variation (gcv) values ranging from 10.15–15.97%. This corresponds to specific activities of approximately 14,300–15,900 TIU/mg protein. This is close to the upper limit of previously reported values of specific activity. We conclude that the precision of this determination compared with the wider range of values in the literature (8,000–16,000 thrombin inhibitory units [TIU]/mg) results from the use of good quality standard α-thrombin by all laboratories. This study has important implications for hirudin standardisation.
A Novel Polymorphism in Glycoprotein IV (Replacement of Proline-90 by Serine) Predominates in Subjects with Platelet GPIV Deficiency
Authors: Kashiwagi Hirokazu , Honda Shigenori , Tomiyama Yoshiaki , Mizutani Hajime , Take Hironori , Honda Yumiko , Kosugi Satoru , Kanayama Yoshio , Kurata Yoshiyuki , Matsuzawa Yuji 
Published: July 2018

SummaryTo clarify the molecular basis of the deficiency of glycoprotein IV (GPIV) of the platelet surface, we analyzed GPIV cDNA synthesized from platelet RNA of five unrelated Japanese subjects whose platelets did not express GPIV.We confirmed the presence of normal-sized GPIV mRNA in platelets from subjects with GPIV deficiency. The sequence of platelet GPIV cDNA from GPIV deficient subject showed three differences when compared with the published sequence; 1) a replacement of a 478CCT codon for proline-90 by TCT for serine, 2) a four-base insertion in the 3′-noncoding region, and 3) a substitution of A for 79C in the 5′-noncoding region. The replacement of Pro90 by Ser predominates in subjects with GPIV deficiency; that is, four out of five platelets with GPIV deficiency contained GPIV mRNA encoding GPIVSer-90, while all platelets from 17 GPIV positive subjects had GPIV mRNA encoding GPIVPro-90. The sequence of platelet GPIV cDNA which did not encode GPIVSer-90 from a subject with GPIV deficiency revealed no abnormality in the coding region. The four-base insertion in the 3′-noncoding region and the substitution of A for 79C in the 5′-noncoding region seems to be unrelated to the expression of GPIV.The substitution of Ser for Pro90 might alter the GPIV structure or impair GPIV biosynthesis, resulting in a lack of detectable GPIV. This hypothesis remains to be tested.