bluuebunny/crossref_metadata_2025_split huggingface dataset:
PLATELET ADHESION AND THROMBIN DEPENDENT AGGREGATION OF PATIENTS WITH AN UREMIC BLEEDING TENDENCY
Authors: Zwaginga Jaap J , de Groot Philip G , Sixma Jan J 
Published: August 2018

Five patients with chronic renal insufficiency (CRI) presented a Simplate bleeding time of > 30’, two patients had normal bleeding times (< 9’)- Blood was collected before standard hemodialysis into 19 mM citrate (plasma concentration). It was circulated fojr 5’ through an annular perfusion chamber at a shear of 1300 s™1 over inverted umbilical artery segments. CRI blood’s hematocrit was raised to .3 by adding their own RBC’s. Control whole blood perfusates with Ht .3 were made by addition of their own plasma. After perfusion platelet adhesion on the artery was evaluated by microscope, corrected for platelet count of the perfusate and given as percentage surface covered. Control donors showed a 37.4 ± 5.2% coverage not different from ‘bleeding’ patients 38.0 ± 4.5% ’non bleeding’ CRI patients: 32.3 ± 3.9. We also perfused blood of three ’bleeding’ CRI patients in a new thrombus forming system. In a rectangular perfusion chamber (J Lab Clin Med 1983, 522-532) blood anticoagulated with low molecular weight heparin (Fragmin1, Kabi Vitrum) was circulated over tissue factor containing matrix of 43-phorbol 12-myristate 13-acetate perturbed endothelial cells. Locally formed thrombin stimulated platelet aggregation on this matrix. Aggregation was expressed as percentage of spread platelets covered with aggregates. Perfusions with the following perfusates were performed: whole blood of controls (WBc) and patients (WBp), CRI platelets with normal plasma and RBC’s (A), CRI plasma with normal platelets and RBC’s (B) and normal platelets with normal plasma and RBC’s (C).Platelet adhesion of CRI whole blood is not defective, aggregation, however, is. Uremic platelets in normal plasma may have an adhesion defect (A). The defective aggregation caused by uremic plasma (B) seems to be corrected for uremic platelets in normal plasma (A).
EFFECT OF DEXAMETHASONE ON ENDOTHELIAL EXTRACELLULAR MATRIX FORMATION AND ON ITS REACTIVITY TO PLATELETS IN A PERFUSION SYSTEM
Authors: Samaden A , Piovella F , Vigotti M , Bendotti C , Fregoni V , Ricetti M M , Montecchio G P 
Published: August 2018

We previously demonstrated that dexamethasone increases fibronectin (FN) expression by human umbilical vein endothelial cell (HUVEC) as well as its incorporation in the extracellular matrix (EM). FN is primarily involved in platelet/vessel wall interactions as well as in cell attachment to substrates. The in vivo anti-haemorragic effect of glucocorticoids could therefore be related either to a better spreading and attachment of endothelial monolayer to the basement membrane or to an increase of vessel wall reactivity to platelets. To further investigate this, we studied the effect of dexamethasone treatment on EM reactivity to platelets in an in vitro perfusion system. Second passage HUVEC were seeded on glass coverslips at a density of 105/cm2 and treated with dexamethasone 1.0 μM for 48 hours. EM were prepared by exposure to 0.1 M NH4OH for 30’. Coverslips carrying the EM were perfused with citrated whole blood in a flat perfusion chamber(*) at wall shear rates of 300 and 900 sec™1 for 5’. Platelet adhesion to EM was evaluated by a morphometric method. The number of platelet adhering to EM at both shear rates was significantly increased by dexamethasone treatment, (+51.9% at 300 sec™1 (p<0.001) and +24.3% at 900 sec™1 (p<0.01)). Our results demonstrate that dexamethasone increases endothelial EM reactivity to platelets possibly through an increase of FN deposition. This, together with FN effect on cell spreading and anchorage to EM, might be responsible for the antl-haemorrhagic action of glucocorticoids.(*) K. Sakanassen et al . , J . Lab. Cl in . Med. 102:522, 1983
IS THE ENDOTHELIAL EXTRACELLULAR MATRIX THROMBOGENIC OR THROMBORESISTANT? EFFECT OF PREPARATION AND 13-HODE LEVELS
Authors: Buchanan M R , Bastida E , Aznar-Salatti J , de Groot P 
Published: August 2018

It is generally thought that the extracellular matrix (ECM) is thrombogenic.However,one of us (MRB) has reported that the ECM is thromboresistant,and postulated that this was due to the release of endothelial cell (EC) 13-hydroxyoctadecadienoic acid (13-HODE) into the ECM. To test this possibility, we measured platelet adhesion (PLT ADH) onto cultured ECs and their ECMs exposed by 3 methods. We also extracted the ECMs for HPLC analysis of 13-HODE.PLT ADH was expressed as i)adhesion of 3H-adenine labelled platelets/mm2 of ECs or ECMs under static conditions, and ii) % surface^ area coverage measured morphometrically following 5"perfusion with citrated whole blood at 1300 sec-1 in the flat chamber.ECMs were prepared by removing the EC monolayers by freeze thawing , cellulose acetate stripping or NH4OH treatment. PLT ADH to ECs under static and flow conditions were 4700±240/mm2 and 0.1%, respectively, and were associated with 12,6± 1 pg of 13-HODE/mm2 of EC surface (M+SEM). Removal of the ECs by freeze thawing or stripping, resulted in a 18% and 25% increase in PLT ADH to the ECM,under static and flow conditions respectively, and a 80% decrease in ECM associated 13-HODE level. Removal of the EC by NH4OH resulted in a 380% and 770% increase in PLT ADH to the ECM in static and flow conditions. 13-HODE was undetectable.These data support the hypothesis that 13-HODE released from ECs influences the ECM thrombogenecity, and indicate that the residual amounts of components present in the ECMs following EC removal is influenced by the method of ECM preparation.
THE “MALMO“ EPITOPE OF FACTOR IX: PHENOTYPIC EXPRESSION OF THE “VIKING“ GENE
Authors: Graham J B , Lubahn D B , Kirshtein J D , Lord S T , Nilsson I M , Wallmark A , Ljung R , Bosco J , Frazier L D , Ware J L , Lin S-W , Stafford D W 
Published: August 2018

The epitope of a mouse monoclonal AB (9.9) which detects a Factor IX (F.IX) polymorphism in the plasma of normal persons (PNAS 82:3839, 1985) has been related to not more than 6 AA residues of F.IX by recombinant DNA technology. The same 6 residues define Smith’s polymorphic epitope (Am. J. Human Genet. 37:688, 1985 and in press). This region of F.IX contains the alanine:threonine dimorphism at residue 148 first suggested by McGraw et al. (PNAS 82: 2847, 1985) and established by Winship and Brownlee with synthetic DNA oligomers (Lancet in press). Using synthetic DNA probes, we have found that the DNA difference between positive and negative reactors to 9.9 is whether base pair 20422, the first pair in the codon for residue 148, is A:T or G:C. We can conclude that 9.9 reacts with F.IX containing threonine but not alanine at position 148.The F.IX immunologic polymorphism-whose epitope we are referring to as “Malmo”-is, not surprisingly, in strong linkage disequilibrium with two F.IX DNA polymorphisms, TaqI and Xmnl. The highest frequency of the rarer Malmo allele in 6 disparate ethnic groups was in Swedes (32%); a lower frequency (14%) was seen in White Americans whose ancestors came overwhelmingly from the Celtic regions of the British Isles; it was at very low frequency or absent in Black Americans, East Indians, Chinese and Malays. A maximum frequency in Swedes and absence in Africans and Orientals suggest that the transition from A:T to G:C occurred in Scandinavia and spread from there. The history of Europe and America plus the geographical distribution of the rare allele lead us to suggest that this locus might be designated: “the Viking gene”.
MYOCARDIAL SALVAGE BY COMBINED TREATMENT WITH RECOMBINANT SINGLE-CHAIN UROKINASE-TYPE PLASMINOGEN ACTIVATOR AND RECOMBINANT HUMAN SUPEROXIDE DISMUTASE IN A CANINE CORONARY THROMBOSIS MODEL*
Authors: Finke U , Schneider J , Friderichs E , Flohé L , Giertz H 
Published: August 2018

Recanalization of thrombotic coronary occlusion with fibrinolytic treatment is a promising approach to salvage jeopardized ischemic myocardium. However, the success of thrombolytic treatment of myocardial infarction may be curtailed by the risk inherent to reperfusion. Cell damage upon reoxygenation after an ischemic period is tentatively attributed to the formation of oxygen-derived free radicals. Improved myocardial salvage is therefore expected from coadministration of a free radical scavenger and fibrinolytic treatment. We tested this hypothesis in a canine model of left anterior circumflex coronary artery (LCX) thrombosis. Thrombolysis was achieved with the fibrin- selective single-chain urokinase-type plasminogen activator of recombinant origin (r-scu-PA). As enzymatic scavenger of oxygen radicals recombinant human superoxide dismu-tase (r-HSOD) was used. The three experimental groups were: group I (n=4) did not receive any treatment after LCX thrombosis; in group II (n=9) at 100 min after LCX thrombosis r-scu-PA (20 μg/kg/min i.v. for 30 min) was infused; dogs in group III (n=8) received concomitant treatment with r-scu-PA and r-HSOD (10 mg/kg i.v. for 60 min). Infarct size as percent of the risk zone was 38.2 ± 4.1 in group I, 25.3 ± 3.7 in group II (p ≤ 0.05 vs group I) and 14.9 ± 3.2 in group III (p ≤ 0.05 vs group II). Incidence of reperfusion arrhythmias and increase in plasma CK were significantly diminished by r-HSOD when compared to dogs receiving r-scu-PA only. There were no significant differences in hemodynamic parameters between the groups. In conclusion, in terms of infarct size reduction, suppression of reperfusion arrhythmias and attenuation of intracellular enzyme release the combined treatment with r-scu-PA and r-HSOD yielded a significant higher myocardial salvage versus thrombolytic treatment alone in a canine LCX thrombosis model.* This work is part of the doctoral dissertation of Miss U. Fincke
INFLUENCE OF RECOMBINANT PRO-UROKINASE ON THE HEMOSTATIC SYSTEM IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION
Authors: Schmitz-Huebner U , Ostermann H , Mathey D G , Schofer J , Diefenbach Ch , Erbel R 
Published: August 2018

Recombinant unglycosylated pro-urokinase (recombinant single chain urokinase-type plasminogen activator, CG4509) was given to twelve patients (pts.) with acute myocardial infarction as a 20 mg bolus followed by a 60 mg intravenous infusion (iv.inf.) over 1 hour and to twelve pts. as a 10 mg bolus followed by a 30 mg iv.inf. over 1 hour. Reperfusion was angiographically confirmed in 9/12 pts. with the higher dose and in 6/12 pts. who obtained the lower dose. Different parameters of hemostasis were determined before administration, 30 min after the beginning of inf.,at the end of inf., 60 min thereafter and 6-12 hours afterwards .The most significant systemic changes were observed 60 min after the end of inf. when the following mean values ± SEM were determined (pre-inf. values in brackets):Fibrinolytic activity in plasma determined on fibrin plates was highest in both groups 30 min after the beginning of inf. and hardly measurable 60 min after the end of inf. No bleeding complications were observed. Based on these results,a randomized double-blind multicenter trial was started to study the effects of 80 mg CG 4509 versus 1.5 million U streptokinase iv.
THE EFFICACY AND RELATIVE FIBRIN SELECTIVITY OF PROUROKINASE IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION
Authors: Loscalzo J 
Published: August 2018

The use of thrombolytic agents in acute myocardial infarction has gained widespread acceptance as an important early therapeutic option. Acute coronary thrombosis has been found in approximately 80% of patients with acute infarction and the use of standard thrombolytic agents opens these occluded vessels in most cases. Unfortunately, in many individuals standard agents also produce a systemic lytic state with its attendant hemorrhagic complications. Prourokinase (PUK) has been shown to be a relatively fibrin selective thrombolytic agent in vitro owing to its localized conversion to urokinase at the clot surface. Because of this desirable property, we studied the efficacy and selectivity of PUK in vivo in 19 patients with acute myocardial infarction. Each of these patients was documented by angiography to have a totally occluded infarct-related artery. Each patient was treated within six hours (range: 2 to 5.8 hours) of the onset of symptoms with 62.5 mg of PUK derived from the human kidney cell line, TCL598, infused intravenously over 90 minutes. Complete vessel patency was achieved in nine patients within 61 ± 19 minutes of the start of the infusion without apparent hemorrhagic complications. We evaluated the effect of PUK on fibrinogen, on nonspecific fibrinogen degradation products (FDP) the the fibrinogen/fibrin I peptide, Bβ 1-42, as well as on the specific fibrin degradation products, D-dimer (XDP) and the fibrin II peptide, Bβ 15-42. Values for these parameters measured before and at the end of the 90-minute infusion of PUK are given as the mean ± S.E.M.We conclude that PUK is an effective agent with which to achieve coronary thrombolysis and that at the doses used in this study, it aDDears to be relatively fibrin selective.
ANTITHROMBOTIC EFFECTS OF TISSUE-TYPE PLASMINOGEN ACTIVATOR AT PHYSIOLOGICAL BLOOD LEVELS
Authors: Witt W , Baldus B , Donner P 
Published: August 2018

Effective thrombolysis in human patients and experimental animals by tissue-type plasminogen activator (t-PA) usually requires t-PA plasma levels in the microgram range. Compared to that physiological plasma levels of t-PA are about 100 - 1000 times lower. To investigate the effects of t-PA at physiological blood levels rat studies were performed in vitro and in vivo employing highly purified recombinant single-chain t-PA (sct-PA: 500,000 IU/mg).t-PA activity in rat whole blood as assessed by dilute blood clot-lysis time (DBC-LT) was increased by addition of sct-PA as low as 3 ng/ml (20 % decrease in DBC-LT). Injection of brady-kinin 10, 100 and 1000 μg/kg i.v. shortened DBC-LT to 54, 23, and 10 % of controls corresponding to the effect of about 10, 30, and 100 ng/ml sct-PA added in vitro. Infusion of sct-PA 15 - 450 μg/kg/h i.v. shortened DBC-LT ex vivo dose-dependently by 20 - 90 % at steady state levels (n = 5). In the same dose range sct-PA inhibited thrombus formation along a silk thread introduced into an arteriovenous shunt in anaesthetized rats. The reduction in thrombus dry weight was dose-dependent amounting to 33 - 67 % of preapplication values (n = 5 - 8) at 15 - 450 μg/kg/h i.v. sct-PA. Already 50 μg/kg/h sct-PA corresponding to a sct-PA activity of about 15 ng/ml displayed a significant (a = 0.05) effect in this model.The results of this study suggest that t-PA present at physiological resting or activation (bradykinin) levels during acute clot formation may have potent antithrombotic efficacy. This study provides further evidence for the importance of a balance coagulation-fibrinolysis which can be influenced on both sides towards thrombophilia as well as to achieve antithrombotic therapy, e.g. by elevating plasma fibrinolytic activity with low-dose t-PA treatment or with drugs which stimulate the endogenous fibrinolytic potential.
INTERACTIONS BETWEEn PGE2 AND INHIBITORS OF PLATELET AGGREGATION THAT ACT THROUGH cAMP
Authors: Gray S J , Heptinstall S 
Published: August 2018

PGE2 has a biphasic effect on platelet aggregation with low concentrations of the prostaglandin potentiating aggregation and high concentrations inhibiting it. In this investigation we have studied the interaction of PGE2 with agents that inhibit platelet aggregation through an effect on cAMP. The agents chosen raise the level of cAMP in platelets by different mechanisms: PGI2, PGD9 and adenosine combine with specific surface-located receptors and stimulate adenylate cyclase (AC) via a guanine nucleotide-binding protein (GNBP), forskolin stimulates AC directly, and AH-P 719 and DN 9693 inhibit cAMP phosphodiesterase (PDE). ADP-induced platelet aggregation was measured in platelet-rich plasma and cAMP was measured in platelets labelled with 3H-adenine.PGE2 alone potentiated platelet aggregation at concentrations from 10™8 -10™6 M and inhibited aggregation at 10™5M. PGE2 did not reduce cAMP levels at any concentration and increased cAMP levels at concentrations > 10™6 M, profcably by stimulating AC.PGI2 (10™9 -10™8 M), PGD2 (10™7 -5×10™6 M) and adenosine (8×l0™5-2×10™4 M) increased the level of cAMP in platelets and inhibited aggregation these changes were reversed by low concentrations of PGE2 (10™8-10™6M).Forskolin (5×10™6-2.5×10™5M), AH-P 719 (10™7-10™5M) and DN 9693 (5×10™6 -10™5M) increased the level of cAMP in platelets and inhibited aggregation. However, PGE2 did not reverse the inhibitory effects of these particular agents. In contrast, PGE2 potentiated the effects of the agents at all the concentrations of PGE2 that were tested (10™8-10™5M).The different results obtained with PGE2 in combination with agents that act via surface-located receptors compared with agents that stimulate AC directly or act through PDE, suggest that PGE2 may potentiate platelet aggregation by acting at a point between the platelet receptor and AC i.e. GNBP.PGE2 is one of the major prostaglandins synthesised by human microvascular endothelial cells and interstitial cells of the renal medulla. Since it reverses the inhibitory effects of some AC stimulators but adds to those of PDE inhibitors, the latter may have greater potential as anti-thrombotic agents in the micro-circulation and intra-renal circulation.
CONTENTS OF PHYLLOQUINONE AND MENAQUINONE FAMILY IN SERUM AND FECES FROM HUMAN NEWBORN INFANTS
Authors: SHIRAHATA A , ASAKURA A , NAKAMURA T , YAMADA K 
Published: August 2018

A sensitive and specific method for the determination of phylloquinone (PK) and menaquinone families (MK-n), between MK-4 and MK-10, was developed. Vitamin K (VK) was extracted from serum and feces with n-hexane-ether, and purified with silica gel column and short alumina column. Eluted VK was separated by high performance liquid chromatography using Cosmosil 5 Cie column with ethanol-water as a mobile phase. The separated VK was detected by a fluorometry after its reaction with ethanolic sodium boro-hydride in a reaction coil connected by one-line to a chromatographic column. Minimum detectable quantities of PK, MK-4 and MK-7 were 0.1, 0.1 and 0.15 ng/ml, respectively.In normal adult serum, PK, MK-4, MK-5, MK-6, MK-7 and MK-8 were detected. The meaniSD values of PK and MK-n from normal adult serum were 3.0±1.4 (PK), 0.3±0.2 (MK-4), 0.9±0.4 (MK-5), 0.3 ±0.3 (MK-6), 3.8±1.4 (MK-7) and 0.3±0.2 (MK-8)ng/ml, respectively. On the other hand, VK was not detected in 19 umbilical blood samples, excluding 3 samples in which 0.7, 1.0 and 2.5 ng/ml of PK were detected. In 7 healthy newborn infants under 8 days of age, VK was not detected excluding 3 cases. Of these 3 cases, in one case, 3.16 ng/ml of PK was detected, and in the other two cases, 1.1 and 1.5 ng/ml of MK-7 were detected. In 11 infants at one month of age, PK ( 10 cases ) and MK-7 ( 5 cases ) were detected, and mean+SD values of PK and MK-7 in the detected group were 0.55±0.44 and 0.62±0.18 ng/ml, respectively. VK was not detected in plasma of infants with primary hemorrhagic disease of the newborn ( 4 cases ) and infantile vitamin K deficiency ( 2 cases ). With a wide variation of VK content in each samlpe, PK and all MK families were detected in feces from normal adults. On the other hand, only PK and MK-7 were detected in meconium collected from 6 normal newborn infants before initial feeding. The contents of VK in meconium were less than one percent of those in adult feces. These results indicate that VK supply from maternal side in utero and from intestinal flora after birth is very poor in newborn infants.
THE ACTION OF HEPARIN IN PLASMA
Authors: Coenraad Hemker H 
Published: August 2018

Much is known about the influence of heparin on the interaction between coagulation proteases and antithrombin III. In the complex milieu of clotting plasma and a fortiori in platelet rich plasma many proteins compete for the heparin, the proteases are partly protected from AT III (-heparin) action and several antiproteases compete for one protease. Also the concentrations of the reactant vary in the course of the clotting process. This makes it difficult to obtain a clear insight in the action of heparin in plasma from studies on purified system only. We therefore developed a method that allows us a) to measure the breakdown constant of endogenously generated thrombin in plasma and to determine what part of it is due to bindingα2 macroglobulin, b) derive the time course of prothrombinase activity from the thrombin generation curve. This method allows us to study separately the action of heparin on prothrombinase and on thrombin.Using this method we could show that: a) Classical heparin acts primarily on thrombin. Its action on other activated clotting factors is of secondary importance,b) The product activation of thrombin isespecially important in the intrinsic pathway, the thrombin dependent activation of factor VIII is the process that determines the onset of explosive thrombin formation. This explains why the APTT is much more sensitive to heparin than the PT is. c) The low molecular weight heparins that we. studied can be divided into two classes: the S type heparins, that, like unfractionated heparin, act practically only on thrombin and the P type heparins that do not act on thrombin but do inhibit prothrombinase. The synthetic pentasaccharide of Choay et al. is a typical example ofthis last group, d) We demonstrated a cooperative effect between thromboplastin and platelets that is mediated via thrombin.It is expressed as a shortening of the agphase of thrombin formation in plateletrich plasma, e) Heparin, but also other antithrombotic drugs inhibit the cooperative effect mentioned above. This suggests that this effect is a good candidate for the screening of antithrombotic drugs, f) The amount of thrombin formed in platelet rich plasma is hardly influenced by concentration of heparin that completely inhibits the formation of thrombin in platelet poor plasma. This is caused by the release of platelet factor 4. g) S type low molecular weight heparins can be conveniently standardized with a standard of classical heparin. P type low molecular weight heparins require a P type standard preparation.