bluuebunny/crossref_metadata_2025_split huggingface dataset:
LONG-TERM COUMAROL PLUS SMALL DOSE ASA THERAPY IN PATIENTS WITH PROSTHETIC HEART VALVE. SOME QUESTIONS OF LABORATORY CONTROL
Authors: Boda Z , Pfliegler G , Tornai I , Udvardy M , Hársfalvi J , Rak K 
Published: August 2018

Thromboembolism in patients with prosthetic heart valves remains a major time-related problem (Sullivan 1971, Dale 1976, Chesebro 1983). Patients receiving anticoagulant plus antiplatelet agent have the lowest incidence of thromboembolism but the risk of bleeding is not negligible. The laboratory control of combined therapy is unsolved.This study considers the thromboembolic prophylaxis of 38 patients with prosthetic heart valve. Cou-marol treatment was combined with ASA (1 000 mg/week, 36 months follow up).Prothrombin ratio was used in control of the oral anticoagulant therapy. Malondialdehyde production was measured parallel with the so-called malondialdehyde-ratio (MDA-ratio = malondialdehyde level of patient/ control plasma). MDA-ratio, platelet aggregation, thromboxane and prostacycline metabolites were studied 48 hours after 500 mg ASA intake. The average of MDA-ratio was 0.42 ± 0.23 (from 137 measurements). The therapeutic range of MDA-ratio is 0.7 - 0.2. Value below 0.2 means overdosed, over 0.7 means an ineffective ASA therapy. Normal first and second phase platelet aggregation was observed in 23 % of cases when MDA-ratio was below 0.5. Only in 4 % of patients with MDA-ratio over 0.7 was found an abnormal platelet aggregation. The mean prothrombin ratio was 1.59 ± 0.22.No gastrointestinal bleeding or thromboembolism was observed during the 36 months follow up. Contrary to the literary data (Chesebro 1983) coumarol plus small dose ASA did not result excessive bleeding and can be suggested for patients with prosthetic heart valve. Examination of both the prothrombin and the malondialdehyde ratio with study of platelet aggregation is recommended as laboratory control.
EFFECTS OF HYPER0XIC AND HYPOXIC CONDITIONS ON ALBUMIN TRANSPORT ACROSS CULTURED ENDOTHELIAL MONOLAYERS
Authors: Bizios R , Holleran L A , Ladd T P , Iveson R D 
Published: August 2018

Transport of albumin across cultured bovine pulmonary artery endothelial monolayers was studied under control (ambient air), hyperoxic (95% O2, 5% CO2) and hypoxic (95% N2, 5% CO2) conditions at 37°C over 3 hours. The experimental system consisted of two compartments separated by the endothelial monolayer grown to confluence on a gelatinized polycarbonate membrane (0.8 μm pore diameter). Albumin (4 gm% in PBS) solution and PBS buffer were placed on the luminal and abluminal sides of the confluent endothelial monolayer respectively. Albumin concentrations in the abluminal compartment at various time intervals were determined (Lowry assay) and the results are shown in the table.Compared to control, exposure to hyperoxia resulted in increased albumin transendothelial transport by one order of magnitude for time intervals up to 1 hr, and by over 50% for later times. In contrast albumin transendothelial transport under hypoxic conditions was comparable to the results obtained under control conditions. The results of this study indicate that hyperoxia greatly affects the transport properties of endothelium. (Supported by the Whitaker Foundation.)
MODULATION of PROSTACYCLIN PRODUCTION BY HUMAN UMBILICAL VEIN ENDOTHELIAL CELLS WITH ECGF/HEPARIN MEDIUM : ROLE OF CELLULAR DENSITY AT CONFLUENCE
Authors: BOUTHERIN-FALSON O , BLAES N 
Published: August 2018

Prostacyclin (PGI2) is a major product of arachidonic acid metabolism in vascular endothelial cells. In addition to the role of exogenous agents, its production could be modulated by culture conditions : proliferative state, medium renewal, subcultivation... The use of endothelial cell growth factor (ECGF) associated with heparin has been shown to improve human endothelial cell proliferation. Here we report that human umbilical vein endothelial cells (HUVEC) grown in that medium produce less prostacyclin than without growth factor.HUVEC were cultured in RPMI-199 1:1 + 20% fetal calf serum, added or not with ECGF (Bovine hypothalamus extract BTI Cambridge, 24 ug/ml) and heparin (from porcine intestinal mucosa, Signa, 90 ug/ml). After 4 days in culture, medium was removed and replaced by Tyrode Hepes buffer and basal production was measured after 20 min. Cells were then submitted to 5 min thrombin to assess PGI2 production in stimulated conditions. PGI2 production was estimated by specific radioimmunoassay for 6 keto PGFjalpha. For each point, cell number in the culture was counted after Trypsin EDTA treatment. In the present study, cells grown in ECGF-heparin medium produce lower amount of PGI2, compared to heparin or control medium. This result was observed in both basal and stimulated conditions. For each medium (ECGF-heparin, heparin, control), correlations between PGI2 production per cell and log cell density were shown to be significantly negative.These observations suggest that ECGF effect on PGI2 production could be a consequence of its growth factor activity, notably by the fact that it leads to an endothelial monolayer made of more numerous cells. Since it is now suggested by a number of clinical observations that PGI2 is rather produced in pathological conditions, culture models showing a weak production of PGI2 appear in that connection doser to the physiological conditions.
DUAL EFFECT OF FLUORIDE ON ENDOTHELIAL PROSTACYCLIN PRODUCTION
Authors: Kienast J , Arnout J , Pfliegler G , Deckmyn H , Van Houtte E , Vermylen J 
Published: August 2018

The effects of fluoride at mM concentrations on prostacyclin (PGI2) production by human umbilical vein endothelial cells in culture were investigated. At lower concentrations, with a peak activity around 20-30 mM, sodium fluoride (NaF) caused a slow rise in PGI2 release reaching a maximum of 6 to 8 × control values after 1 hour. With increasing concentrations, the NaF-induced PGI2 production progressively decreased to almost control levels at 100 mM. Preincubation of the cells with 100 mM NaF inhibited thrombin— and A23187-stimulated PGI2 production by 46 % and 64 % respectively. The response to NaF was not significantly enhanced by AlCl3 nor was it inhibited by pertussis toxin.The dual, stimulatory and inhibitory, effect of NaF on endothelial PGI2 production as well as its slow mode of action resemble the stimulus-response pattern observed in platelets upon exposure to NaF as it has previously been described by our grcup. Therefore, NaF might be an interesting tool for the investigation of intracellular regulatory processes triggering endothelial PGI2 production, particularly in view of the known capacity of fluoride to activate guanine nucleotide—binding regulatory proteins.
TICLOPIDINE AND PREVENTION OF PLATELET ACCUMULATION IN CAROTID ENDARTERECTOMY. EVALUATION WITH INDIUM-111 LABELED PLATELETS
Authors: Catani L , Vitacchiano G , Scatigna M , Monetti N , Pedrini N , Gugliotta L 
Published: August 2018

In endoarterectomy (EA) the vascular endothelium is removed, thus promoting platelet adhesion and aggregation. This situation may cause microembolic phenomena that manifest at the carotid level with the appearance of TIA in the postoperative period. An interesting method of evaluating platelet behavior “in vivo” consists of the use of indium-111 labeled autologous platelets and the subsequent evaluation of scintigraphic images.We used this method to perform a pilot study on the efficacy of ticlopidine, an antithrombotic drug with platelet antiaggregant activity, in the prevention of platelet accumulation after carotid EA.A total of 20 patients undergoing carotid EA were randomly allocated to receive ticlopidine 500 mg/day (10 patients, T group) or placebo (10 patients, P group) in double-blind conditions. Drug administration was started 5 days before the operation and continued during the postoperative period; infusion of the labeled platelets was performed on the first and scintigraphic evaluation on the second postoperative day.Analysis of the two groups, which were comparable for age, sex, risk factors and associated patologies, showed 3 scintigraphic-positive cases in the T group and 6 in the P group. The fixation index was 1.12 ± 0.18 in the T group and 1.20 ± 0.16 in the P group. One patient in the P group presented an episode of amauros is fugax in the first postoperative day.The results of this pilot study suggest that ticlopidine is effective in preventing platelet accumulation after carotid EA.
PROTECTIVE EFFECT OF A NEW SYNTHETIC COMPOUND: PCA-4230, ON SEVERAL In vivo THROMBOSIS MODELS.
Authors: Ortega M P , Sunkel C , Priego J G 
Published: August 2018

PCA-4230 is a new anti-thrombotic compound which inhibits pla. telet aggregation In vltn.0 and ex. vivo in several species, including man, prolongs the bleeding time and has potent protective ac tivity in several thrombosis models. Phase I trials with different dosage schedules have recently been initiated.In the present study, the effects of PCA-4230 on bleeding time and on several In vivo thrombosis models were studied in mice. Mice were treated with one single oral dose of PCA-4230 (1-10 mg/ kg). One hour after treatment, mice were injected intravenously with four thrombotic challengers {arachidonic acid (AA), thromboxane agonist (U46619), Platelet Activating Factor (PAF) or collagen/epinephrine combination (C/E)} at a dose which induced 80-90% of mortality. The thrombotic agents were prepared in saline. The appropiate doses were dissolved in a volume of 100 μl/mouse. Bleeding time was measured in non-anesthetized mice by the tail transection technique.Effects of compound were recorded from1 to 4 hours after dosage. Acute pre-treatment with PCA-4230 showed a significant dose-depen dent protective effect.Results of each series of experiments are given in the next table.The compound inhibited thrombotic sudden death induced by U46619, PAF or C/E combination, reduced the duration of respiratory distress induced by AA and prolonged bleeding time. Thus, PCA-4230 is protective against a variety of thrombotic stimuli.These results suggest that PCA-4230 may be a promising anti-throm botic drug.
PLATELET DERIVED GROWTH FACTOR (PDGF) BINDS TO HUMAN BONE MARROW FIBROBLASTS AND STIMULATES THEIR PROLIFERATION.
Authors: Bryckaert M C , Wasteson A , Lindroth M , Tobelem G C 
Published: August 2018

A role for the Platelet Derived Growth Factor (PDGF) has been suggested in the abnormal proliferation of bone marrow fibroblasts occuring during myelofibrosis. To investigate this hypothesis, human bone marrow fibroblasts were isolated, and the cultures were characterized by immunofluorescent staining and electron microscopy. Electron microscopy eliminated the presence of endothelial cells by the absence of Weibel-Palade-Bodies. A positive intra and extra cellular antifibro-nectin staining was observed by immunofluorescent staining. The cultured cells didn’t show any labeling with specific antibodies for factor VIII von Willebrand factor, desmin or macrophage. Following the characterization of the bone marrow fibroblasts, using human pure 125I-PDGF, a specific binding of 125I-PDGF was demonstrated. The binding reached a plateau after 3 hours at 20°C, and after 4 hours at 4°C. Addition of unlabeled PDGF decreased this binding until 25 %.Saturation curve and scatchard analysis indicated two classes of sites with respectively 21,000 sites/aall and 37.000 sites/cell with an apparent Kd of 0.3 X 10-10 M and 0.5 X 10-9 M. Normal human serum at a concentration of 20 % induced a maximal DNA synthesis measured by-3H thymidine incorporation. When PDGF was added alone to the	cultured fibroblasts at a concentration of 15 ng/ml, it induced a maximal DNA synthesis of 400 %.In the presence of 5 % of Platelet Poor Plasma (PPP), the same concentration of PDGF (15ng/ml) increased the incorporation of 3H thymidine up to 900%.In conclusion i) PDGF binds to human bone marrow fibroblasts, ii) PDGF stimulates their proliferation. These results are in favour of a role of PDGF in the proliferation of bone marrow fibroblasts associated with the development of myelofibrosis.
THE FUNCTIONAL DOMAIN OF PLATELET MEMBRANE GLYCOPROTEIN lb FOR VON WILLEBRAND FACTOR AND THROMBIN-BINDING
Authors: Taki M , Sato K , Ikeda Y , Yamamoto M , Watanabe K 
Published: August 2018

In this paper, we have examined the functional domain of platelet membrane glycoprotein lb (GPIb) by using elastase and a monoclonal antibody against GPIb which specific inhibits both von Willebrand factor (vWF) and thrombin interaction with platelets. Elastase was purified from human granulocytes by using affinity column chromatography according to the method of Okada et al.. A monoclonal antibody against platelet membrane GPIb (56-2) which inhibits both vWF and thrombin-binding to platelets was used for this study. Platelet surface glycoproteins were labelled with 3H by the method of Nurden et al.. Purified GPIb was obtained by a modification of the method of Coller et al. and labelled with 125I using chloramine-T method. Either 3H-labelled platelets or 125I-labelled GPIb was treated with elastase for various time periods. Elastase-treated l25I-GPIb was subjected to immunoaffinity chromatography using 56-2 antibody to determine the functional site of GPIb. Elastase inhibited platelet aggregation or 5-HT release by thrombin, ristocetin-induced platelet agglutination and vWF-binding to platelets in the presence of ristocetin in a dose- and time dependent manner. A fluorogram of SDS-PAGE of 3H-labelled platelets treated with elastase revealed that GPIb band was reduced gradually, and fragments with MW of 97, 70, 60, 47, 44, 37, 25 and 15 KD were released from the platelets. The 47 KD fragment was initially cleaved from the platelets, and subsequently other fragments were digested. Similar results were obtained when purified 125I-GPIb was digested by elastase. When the fragments from purified 125I-GPIb were reacted with 56-2 antibody, only three fragments with MW of 47, 44 and 25 KD were immunoisolated. The electrophoretic mobility of all these three bands was altered under reduced conditions, indicating that all these fragments contain disulfide bonds in their molecules. The 25 KD band showed a much fainter in 3H-labelling than in 125I-labelling.These results suggest that the functional domains of GPIb for both vWF and thrombin-binding may be located in a less glycosylated fragment with a MW of 25 KD on the distal portion of the GPIb molecule, which should contain at least one intramolecular disulfide bond.
INCREASED SPONTANEOUS NUMBER OF MEGAKARYOCYTE COLONIES IN ESSENTIAL THROMBOCYTHEMIA (ET)
Authors: Deschamps J F , Bodevin E , Caen J P 
Published: August 2018

Megakaryocytes were grown from medullary progenitor cells using the plasma clot technique, with 5 % human serum and with or without 2,5 % PHA-LCM. Using this technique megakaryocyte cultures were done in 5 patients essential thrombocythemia (ET) ( platelet count :0,6 x 106 to 1,4 x 106 /μi) before chemotherapy and antiplatelet agents and in 2 patients with secondary thrombocytosis (ST) (platelet count : 0,65 x lO6 and 0,8 x 106 /μi) corrected after effective anti-bacterial or iron therapy. The results were as followsx number of colonies mean number (in brackets) of cells per colonyIt appears therefore that in ET, megakaryocyte progenitors grow without PHA-LCM and show however a better proliferation in its presence. On the contrary in ST, PHA-LCM is required for obtaining a 6 times increase of MK colonies. The effect of MK growth under chemotherapy is reported in some of the patients studied before treatment and results analyzed and compared to platelet function involvement
DOES THE MEGAKARYOCYTE CYTOSKELETON REGULATE IRROMBOPOIESIS?
Authors: Heynen M J , Verwilghen R L , Vermylen J 
Published: August 2018

A widely held view of thrombopoiesis is that platelets arise from fragmentation of the periphery of mature megakaryocytes (MK’s). Evidence against this concept was provided by Zucker-Franklin, who showed that platelet plasma membrane is different from that of the MK (freeze-fracture, membrane antigens). Several authors have described contractile processes in MK’sWe have performed detailed electronmicroscopic studies of the numerous small MK's of a subject with congenital macrothrombocytopenia. In the young granular MK’s a central zone with organelles and a thick peripheral zone without organelles can be observed. The absence of elements of the demarcation system in the peripheral zone argues against derivation of the demarcation system from the megakaryocyte plasma membrane. In the mature granular MK’s the heart of the central zone is not occupied by the nucleus, but by an area, free of organelles and membranes, containing fibrillar structures and the centrioles. Elements of the demarcation system, delineating platelet territories, radiate from this fibril-rich area, but do not extend into the very thin peripheral zone. In the platelet producing MK’s the peripheral zone is thicker and the central fibril-rich area is surrounded by separated platelet territories. The peripheral zone shows several openings. In the old MK’s the nucleus is only surrounded by a markedly thickened peripheral zone, which seems to result from contraction of the more extended peripheral zone of the platelet producing MK's.From these observations we conclude that, at least in this patient, platelets are formed inside the MK and are extruded through openings of the peripheral zone. Further studies with cytoskeleton markers are required to confirm that (!) the fibril-rich heart governs the organisation of platelet territories and (2) that platelet extrusion results from contraction of the peripheral zone, the latter however not giving rise to platelets.
SECONDARY FIBRINOLYSIS, PROTEIN C ACTIVATION, PLATELET DECREASE, BUT NOT CONTACT ACTIVATION CAN BE CORRELATED TO FREE THROMBIN ACTION IN EXPERIMENTAL DIC
Authors: Marbet G A , Satiropas P , Pantaleoni C , Duckert F 
Published: August 2018

We have studied the influence of activated coagulation on antithrombotic defence mechanisms in vivo. Conventional coagulation variables, platelets (Tcy), plasminogen (Pig), α2-antiplasmin (AP) , protein C (PC), factor VIII C, factor XII and Cl-inhibitor have been measured before and during reversible tissue thromboplastin-induced DIC in the dog. Free thrombin action as derived from fibrinogen (Fbg) decrease has been expressed as integral of active thrombin concentration over time (φ). Protection by heparin H, pentosan polysulfate PPS or dermatan sulfate DS was studied. DIC had no consistent effect on the behaviour of factor XII and Cl-inhibitor, but led to the consumption (Δ) of the following variables:The Spearman correlation coefficients between and φ in the Δ whole group were all statistically significant and ranged from rs=0.51 (ΔPlg) to rs =0.94 (ΔFbg). The response of major defense mechanisms in vivo quantitatively depends on active thrombin.
THE ARG-GLY-ASP(SER) SEQUENCE OF FIBRONECTIN, AND THE GLYCOPROTEIN IIB-IIIA COMPLEX ARE NOT INVOLVED IN FIBRONECTIN DEPENDENT PLATELET ADHESION IN FLOW
Authors: Nievelstein P F E M , Ottenhof-Rovers M , Pierschbacher M D , Sixma J J 
Published: August 2018

Activated blood platelets interact with fibronectin through it to the glycoprotein IIb-IIIa(GPIIb-IIIa)-complex. The cell attachment site of fibronectin with its crucial arg-gly-asp-(-ser) (RGD(S))sequence is involved in this binding. We have studied the importance of this interaction for the fibronectin dependence of platelet adhesion under flow conditions. An RGDS-containing hexapeptide (GRGDSP) was compared with a non-reactive control peptide (GRGESP). The GRGDSP-peptide inhibited thrombin induced aggregation and adhesion under static conditions at 0.1 mM. This concentration had no effect on platelet adhesion to nonfibrillar collagen type I in flow. GRGDSP at 1 mM had a significant inhibitory effect at 1500 s™1 (8.8 ± 1.4 111In platelets* 105 /cm2, versus 19.8 ± 0.5 for the control). At lower shear rates of 800 and 300 s™1 , where platelet adhesion is also fibronectin dependent, no significant differences were obtained (respectively 11.7 ± 1.1 versus 15.2 ± 2.1, and 11.4 ± 1.0 versus 13.1 ± 0.7).The relation between GPIIb-IIIa and fibronectin dependence was investigated with platelets of a patient with Glanzmann’s thrombasthenia and monoclonal antibodies to GPIIb-IIIa, using endothelial cell matrix (ECM) as a surface. Platelets of normal controls or a patient with Glanzmann’s thrombasthenia showed a inhibition of adhesion in fibronectin free plasma, after the ECM had been preincubated with anti-fibronectin F(ab’)2, of respectively _J5 and 30 percent at 300 s™1 , and 43 and 65 percent at 1300 s™1 . Incubation of platelets with anti GPIIb-IIIa showed inhibition of platelet adhesion at high shear rates. Dependence on fibronectin for platelet adhesion was still observed, even though separate experiments had shown that these anti GPIIb-IIIa antibodies could block binding of radiolabeled fibronectin to thrombin activated platelets. These data suggest the existence of a second binding system from the RGD/GPIIb-IIIa system separate for the interaction of platelets with fibronectin, which may only function when fibronectin is present on a surface.
CHARACTERIZATION OF RECOMBINANT HUMAN SINGLE-CHAIN LOW MOLECULAR WEIGHT UROKINASE (RE-SC-LUK)
Authors: Günzler W A , Wolf B , Flohé L 
Published: August 2018

RE-SC-LUK obtained from recomoinant b. con Bacteria showed a molecular mass similar to that of recombinant two-chain LUK (RE-TC-LUK) as judged from SDS-PAGE. By “Western“ blot analysis immunoreactivity of RE-SC-LUK was observed with monoclonal antibodies directed against the B chain but not with those against the A1 chain of urokinase. N-terminal sequence analysis c RE-SC-LUK showed identity to the A, chain of RE-TC_LUK and provided evidence for its single-chain nature, i.e. integrity of the Lys-Ile bond which is split in TC-UK. In all other respects structural identity of RE-SC-LUK and RE-TC-LUK was demonstrated by fingerprinting of fragments. Similar to recombinant pro-urokinase (RE-SCU-PA), RE-SC-LUK exhibits only marginal amidolytic activity, which is greatly enhanced by treatment with plasmin, but considerable fibrinolytic activity in a fibrin agar plate test.Thus, RE-SC-LUK is characterized as a fragment (residues 136 -411) of RE-SCU-PA, which lacks the “growth factor” and “kringle” domains. Moreover further evidence is provided that a free N-terminus of the B chain is essential for amidolytic but not for fibrinolytic activity of urokinase in more complex systems.