bluuebunny/crossref_metadata_2025_split huggingface dataset:
NEUTRALIZING EFFECT OF PLATELET FACTOR 4 OR HISTIGINE-RICH GLYCOPROTEIN AGAINST LOW MOLECULAR WEIGHT HEPARIN AND UNFRACTIONATED HEPARIN
Authors: Takahashi K , Niwa M , Sakuragawa N 
Published: August 2018

Purpose: Low molecular weight(LMW) heparin shows stronger antifactor Xa(F-Xa) and weaker anti-thrombin(TH) activities compared with unfractionated(UF) heparin, and shows less bleeding tendency in the cases of clinical use. Platelet factor 4(Pf-4) and histidine-rich glycoprotein(HRG) neutralize heparin. We investigated on the heparin neutralizing effects of them to both kinds of heparinMaterials and methods: LMW heparin(Kabi and Pharmuka) and UF heparin(Novo) were used. Antithrombin III(AT-III), HRG(human origin ) and pf-4( bovine origin ) were purified by our methodsTH(Green-Cross) and F-Xa(Sigma) were used. Reaction mixtures for anti-TH or anti-F-Xa were as follows: 1 vol of AT-III( 0.1 U/ml)+
1 vol of heparin( 10 ug/ml)+l vol of pf-4 or HRG(varied)→incubated for 5 min→+l vol of TH(5 U/ml) or F-Xa( 7 nKat/ml)→incubated for 5 min→ + S-2238 or S-2222→ recorded at 405 nm.Results: (1) Pf-4 showed the equivalent anti-TH effect on both kinds of heparin, and 3 ug of pf-4 neutralized 1 ug of heparinOn F-Xa neutralizing effect, 13 ug of pf-4 neutralized 1 ug of UF heparin, but could not neutralize LMW heparin. (2) HRG showed the same results on anti-TH effect of both kinds of heparin, but could not neutralize the anti-F-Xa effect of LMW heparin on the same amount of HRG which neutralized that of UF heparin. Conclusion: Anti-F-Xa effect of. LMW heparin could not be easily neutralized by pf-4 or HRG compared with that of UF heparin.
IN VIVO INTERACTION BETWEEN HUMAN PLATELET FACTOR 4 (PF4) AND PROTAMINE SULPHATE (PS) IN THE PRESENCE OF DIFFERENT GLYCOSAMI-NOGLYCANS (GAGs)
Authors: Celia G , Prosdocimi M , Sasahara A A 
Published: August 2018

Anti-heparin substances, like PF4 or PS, have been studied largely in reference to their ability to neutralize the anticoagulant activity of heparin. On the other hand, few data are available concerning the relationship between GAGs and anti-heparin proteins clearance. We studied the action of PS on human PF4 kinetics in anesthetized rabbits pre-treated with heparin (H, 1000 I.U.), heparan sulphate (HS, 30 mg) and derma tan sulphate (DS, 30 mg). PF4 (given at a dose of 45 μgAg) disappearance reflected its different affinity for the GAGs, with the following half lives (min): control 2.09±0.28, H 14.80±1.47, HS 10.90±1.91, DS 6.87±0.68. Moreover, circulating PF4 (ng/ml) at 1 min was as follows: control 109±8, H 873±134, HS 751±34 and DS 473±15. In another group of H pre-treated rabbits, a bolus injection of PS (10 or 20 mg) caused an immediate disappearance in th.e circulating plasma PF4, from 900±23 ng/ml (1 min after PF4) to 75±11 ng/ml (1 min after 10 mg PS). However, a subsequent H injection 10 min after PS induced a peak release of PF4 (520±21 ng/ml). In a further group of animals pre-treated with HS, the interaction between PS and PF4 was similar to that observed after H treatment. In the last group, pre-treated with DS, the interaction between PF4 and PS was also similar, however, unexpectedly, when 20 mg of PS were given a subsequent bolus of H did not produce any increase of circulating PF4We suggest that PS displaces PF4 from its binding sites on H or HS, thus allowing its uptake by the storage sites in the body, from where it can be harvested again after the subsequent H administration. In the presence of DS again PS is able to displace PF4, however the remaining excess of PS could neutralize the subsequent H injection, thus rendering it unable to induce PF4 release.
EXTRACELLULAR CALCIUM AND PLATELET GLYCOPROTEINS
Authors: Jabbal-Gill I , Johnston G I , Heptinstall S 
Published: August 2018

Platelet membrane glycoproteins lib and Ilia form Ca++-dependent heterodimer complexes that contain binding sites for fibrinogen and therefore are relevant to the ability of platelets to aggregate together. In this study we investigated the effects of extracellular Ca++ on the stability and expression of IIb-IIIa complexes using a IIb-IIIa complex-specific monoclonal antibody M148. Its specificity was examined using crossed immunoelectrophoresis: the antibody reacted only with intact IIb-IIIa complexes and not with either glycoprotein alone.SDS-polyacrylamide gel electrophoresis of immunoprecipitates of soluble glycoproteins that interacted with Ml48 showed that lib and Ilia were present as complexes in Ca++-depleted media at 25°C, pH7.4. However, Ca++-depletion at 37°C, pH7.4 or 37°C, pH8.7 or 25°C, pH8.7 caused dissociation of the complexThe effect of extracellular Ca++ on the expression of IIb-Illa complexes on the surface of intact platelets was studied by a technique which is based upon indirect binding of M148 using a fluorescent- labelled second antibody (FITC-RAM) and measuring the fluorescence per platelet using the FACS IV cytofluorometer. Intact platelets were incubated in Ca++-depleted media at 25°C, pH7.4 or 37°C, pH7.4 either (i) prior to or (ii) after adding M148. At 25°C increased M148-binding was observed, compared to the value prior to Ca++-depletion. This increased binding could be reversed by adding Ca++ back to the preparation. Under condition (i) at 37°C a marked decrease in M148 binding was observed, which could not be reversed by restoring Ca++, while under condition (ii) at 37°C the results were the same as at 25°C.Our studies demonstrate that (a) Ca++-depletion at 37°C and/or alkaline pH causes dissociation of the Ilb-IIIa complex (b) Ca++ depletion at 25°C possibly alters distribution of the complexes thereby increasing their availability to the antibody and (c) M148 prevents the dissociation of complexes in Ca++-depleted media at 37°C, possibly by holding lib and Ilia together
BINDING OF FIBRINOGEN TO PLATELET GLYCOPROTEIN (GP) IIb/IIIa IS CRUCIAL FOR SHEAR-INDUCED PLATELET AGGREGATION
Authors: Ikeda Y , Murata M , Araki Y , Yamamoto M , Watanabe K , Ichitani M , Sakai K , Itagaki I , Mori Y 
Published: August 2018

It is well known that human platelets can aggregate in vitro under certain shear stress without adding aggregating inducers. However, the mechanism of this shear-induced platelet aggregation has not been clarified yet. In this paper, we have investigated the role of fibrinogen and GP IIb/IIIa in shear-induced platelet aggregation. Citrated human platelet-rich plasma (PRP) was subjected to controlled shear stress levels in a polycarbonate cone and plate viscometer at 37°C for 2 minutes. After shearing the particle count was measured by an electronic particle counter. Particles with sizes from 3 to 20 μ cum were considered as single platelets. In unsheared PRP most of the particles were single platelets, but platelet doublets and platelet fragments larger than 3 μ cum were also counted. After exposure to shear rate of 3,600 - 9,000 sec−1 , the particle counts were decreased in a shear rate dependent manner, while LDH leakage from platelets was not significantly increased and 3H-serotonin release was 2-7%. Scanning electronmicroscopy clearly showed the presence of large platelet aggregates when the particle counts were decreased. Platelets from two patients with thrombasthenia and one patient with afibrinogenemia, however, failed to aggregate at a shear rate of 9,000 sec−1. Shear-induced aggregation was inhibited by monoclonal antibody to GPIIb/IIIa (1 μg/ml) and synthetic peptide, Arg-Gly-Asp-Ser, (1 mM). When fibrinogen was added to PRP from a patient with afibrinogenemia, shear-induced aggregation became evident as seen in normal platelets. Apyrase and hirudin showed no effect on shear-induced aggregation. Indomethacin (100 μM) and TXA2 synthetase inhibitor, OKY-046 (100 μM) markedly inhibited aggregation, while TXA2 competitive inhibitor, ONO-3708 (100 μM) exhibited only partial inhibition.Our results indicate that binding of fibrinogen to GPIIb/lIIa is also crucial for shear-induced platelet aggregation and that the exposure of fibrinogen receptor on GPIIb/IIIa may partially depend upon TXA2 synthesis in platelets.
ADHESION OF BLOOD PLATELETS TO THE EXTRACELLULAR MATRIX OF CULTURED CELLS IN WHICH COLLAGEN SYNTHESIS IS IMPAIRED OR INDUCED
Authors: Hindriks G A , de Boer H C , Nieuwenhuis H K , Sixma J J , de Groot P H G 
Published: August 2018

One of the first phenomena in the hemostatic plug formation is adhesion of platelets to the subendothelium or to the perivascular connective tissue. With a rectangular perfusion chamber (Sakariassen et al., J.Lab.Clin.Med.(1983) 102, 522-535) it is possible to study platelet adhesion in flowing blood to extracellular matrix (ECM) of cultured cells.Collegen type I and III play an important role in the adhesion of platelets. To study their role in more detail, cultured cells with changed collagen synthesis were used. For this purpose, we used fibroblasts of a patient with Osteogenesis Imperfecta type I (0.I.)(characterized by impaired collagen synthesis) cultured from a skin biopsy and used in the fourth passage. Platelet adhesion to ECM of 0.1. fibroblasts was decreased in comparison to ECM of normal fibroblasts (8% versus 17% at low shear rates (300 s™1 ) and 5% versus 24% at high shear rates (1300 s™1 ) after perfusion with whole blood for 5 min). No aggregate formation occurred on patient’s matrices, whereas small aggregates were observed on ECM of normal fibroblasts. Addition of ascorbic acid to culture medium of fibroblasts, smooth muscle cells and endothelial cells causes increased collagen synthesis with increased fibril formation. Platelet adhesion to ECM of endothelial cells showed an increased adhesion of 25% only at high wall shear rates (1300 s™1 ). Induction of collagen synthesis in smooth muscle cells resulted in a strong increase of thrombus formation on their matrices. These data indicate that platelet adhesion to the matrix of cultured cells is strongly dependent on the quantity and nature of the reactive collagens.
EFFECTS OF CONSTANT INFUSION OF ILOPROST, A STABLE PROSTACYCLIN DERIVATIVE DURING CARDIOPULMONARY BYPASS
Authors: Walker Isobel D , Davidson J F , Wheatley D J , MacArthur K , Spyt T J 
Published: August 2018

Prostacyclin (PGI2) is a potent inhibitor of platelet aggregation but it is highly unstable. Iloprost (Schering A.G.) is a stable carbacyclin derivative of PGI2 which is also a potent inhibitor of platelet aggregation. The effect of constant Iloprost infusion during cardiopulmonary bypass (CPB) on blood loss, platelet numbers, secretory proteins and platelet sequestration was studied in 50 adult males undergoing CPB for elective coronary vein bypass graft surgery.In a double-blind, randomised, placebo-controlled study (25 patients in each group) intravenous infusion of Iloprost was commenced at 5ng/kg/min immediately after the induction of anaesthesia and increased to 10ng/kg/min when the patient was established on CPB. The infusion was discontinued on completion of CPB. Blood loss and units of blood transfused were not significantly different in the two treatment groups. During CPB, mean platelet numbers fell significantly in both groups but were significantly higher (P<.001) in the Iloprost group than in the placebo group at the end of CPB and until 18-24 hours post CPB (P<.05). Mean plasma thromboxane B2 and β thromboglobulin levels were marginally lower (P<.05 and P<.02) in the Iloprost group but the distribution of platelet factor 4 results were similar in both groups. Post operative spontaneous platelet aggregation was similar in both groups. Platelet sequestration in oxygenators and arterial line filters was assessed using Indium labelled patients’ platelets reinjected immediately after commencing Iloprost infusion. Platelet sequestration was significantly greater in the placebo group than in the Iloprost group both in the oxygenators (placebo 9.2%, Iloprost 3.4% : P<.001) and in the arterial line filters (placebo 4.8%, Iloprost 0.6% : PC.05).Blood pressure was significantly lower in the Iloprost group than in the placebo group throughout the infusion period.Constant infusion of Iloprost during CPB is associated with significantly less platelet sequestration. The importance of this is not only in the conservation of platelet numbers but also the potential reduction in risk of platelet aggregate embolisation.
THROMBOSPONDIN ADSORPTION AND PLATELET ADHESION TO SURFACES
Authors: Adams G A , Hallée C 
Published: August 2018

Recent research into cell adhesion has focused on a tripeptide sequence arg-gly-asp (RGD) that is common to a number of cytoadhesive proteins such as von Willebrand factor, fibronectin and fibrinogen. We have previously reported that thrombospondin (TSP) inhibited platelet adhesion to RGD proteins. On further purification of TSP, the inhibitory activity separated away from the TSP. In this report, we demonstate that TSP adsorbs to surfaces and promotes platelet adhesion and thus may belong to this family of cytoadhesins. TSP was purified by heparin affinity chromatography, ammonium sulfate precipitation and sucrose gradient ultracentrifugation. Final preparations were free of TSP aggregates and gave one band on SDS-PAGE. Washed human platelets were radiolabelled, combined with red blood cells and perfused through protein-coated glass or polyethylene (PE) tubes for 7 mins. at a shear rate of 100 s™1. TSP supported platelet adhesion to the same level as fibrinogen (FG), but less than collagen. Platelets were spread but no thrombi were present on the TSP or FG-coated tubes while thrombi formed on collagen-coated tubes. Levels of adsorption were similar for purified solutions of radioiodinated FG or TSP on both glass and PE surfaces. The competitive interactions between these proteins during adsorption to surfaces indicated at equimolar amounts the TSP and FG both deposited on the surface but as FG:TSP ratio increased FG was preferentially adsorbed. These results indicate that TSP is a cytoadhesive protein for platelets when it is adsorbed to surfaces. Thus, the release of TSP from platelets may promote haemostasis or thrombogenesis.(supported by Ontario Heart Foundation, Canada)
WHAT IS THE OPTIMAL DOSAGE OF LMW HEPARIN IN THE SC TREATMENT OF DEEP VENOUS THROMBOSIS
Authors: Arnesen K E , Handeland G F , Abildgaard U , Gottschalk P , Stene-Larsen G , Nilsen D W T 
Published: August 2018

LMW heparin (LMWH) is better suited for subcutaneous (sc) administration than is UF heparin due to higher bioavailability and slower elimination. Optimal dosage for sc treatment of DVT has not been defined. Our previous study suggested that LMWH should be given in doses according to bodyweight (bw), and that sc injection of 100 anti-Xa U/kg bw/12 hrs might result in therapeutic plasma levels (Holm et al. Haemostasis 16, supl 2,30-37, 1986). This dosage is now being evaluated in an open study including patients with venographically proven DVT. Excluded were patients with pulmonary embolism, thrombosis in the IIiacal vein and females beyond 70 yrs of age. LMWH (Fragmin) is administered sc for at least 5 days. Venography is repeated the last day of treatment and evaluated blindly (Marder score). Compared to the previous study in which doses were given according to age and sex, the present protocol results in more uniform and predictable heparin plasma concentrations : Peak concentration day 2 now ranged 0.40-0.75 U/ml (mean 0.58) (n = ll) as compared to the three-fold wider range (0.261.20 U/ml)(mean 0.57)(n = 29) in the previous study. The 12 hrs plasma heparin profile was determined on day 3. Peak concentrations in the 0.44-0.72 U/ml range were found 2.5-4 hrs after injection. The plasma heparin activity was subtherapeutic (< 0.2 U/ml) the last 3-6 hrs of the 12 hrs period. The heparin activity at the next injection averaged 0.05 U/ml (range 0-0.ll). Day to day variation of peak heparin activity in the individual patient, expressed as CV, ranged 11-22% and there was no heparin accumulation.Conclusions: SC treatment of DVT with LMWH 100 anti-Xa U/kg bw/12 hrs results in peak plasma heparin activity in the 0.40-0.75 U/ml range. The plasma heparin activity was below therapeutic level 3-6 hrs of the 12 hrs period indicating that a larger dose (250 U/kg bw/ 24 hrs divided into 2 or perhaps 3 injections) is preferable.
DOES LOW-DOSE PERI-OPERATIVE HEPARIN ADMINISTRATION AFFECT MORTALITY FOLLOWING MAJOR ABDOMINAL SURGERY?
Authors: Hedges A R , Parker C J , Kakkar V V 
Published: August 2018

Current evidence suggests that peri-operative low-dose heparin administration reduces the post-operative frequency of fatal pulmonary embolism and may also reduce the frequency of fatal myocardial infarction. Evidence is now accumulating that anticoagulants affect the course of malignant disease, in particular the formation of metastases. Malignant cells disseminated during surgery may be responsible for metastasis formation.The aim of this study was to discover whether administration of peri-operative low-dose heparin had any effect on mortality. A retrospective analysis of 1,232 patients undergoing elective abdominal surgery was performed. 658 patients received no heparin and 574 patients received heparin prophylaxis subcutaneously. The two groups were well matched for age, sex, type of operation performed and distribution of pre-existing disease. The number and causes of death are shown below.Low-dose peri-operative heparin administration reduces postoperative mortality. This reduction is only partly explained by a reduction in cardiopulmonary cases, more significantly there Is a reduction in death due to disseminated malignancy.A prospective study is planned in patients undergoing operations for malignancy to confirm this finding.
HIGH AFFINITY CALCIUM BINDING TO DOMAINES OF PROTEIN C THAT ARE HOMOLOGUS TO THE EPIDERMAL GROWTH FACTOR
Authors: KÖhlin A , Stenflo J 
Published: August 2018

In addition to γ-carboxyglutamic acid (Gla)-dependent calcium binding all of the vitamin K-dependent plasma proteins, except prothrombin, have one or two high affinity calcium binding sites that do not require the Gla residues. A common denominator among these proteins (factors IX, X, protein C, protein Z and protein S) is that they have domaines that are homologus to the epidermal growth factor (EGF) precursor. In factors VII,IX,X, protein C and in protein Z the aminoterminal of two EGF homology regions contain one residue of β-hydroxyaspartic acid (Hya) whereas in protein S the aminoterminal EGF homology region contains Hya and the three following contain one β-hydroxyasparagine residue each.In an attempt to elucidate the role of the EGF homology regions in the Gla independent calcium binding we have isolated a tryptic fragment (residue 44-138) from the light chain of human protein C. The fragment was isolated using a monoclonal antibody that recognizes a calcium ion stabilized epitope that is expressed both in intact protein C and in protein C lacking the Gla domaine.The antibody bound the isolated EGF homology region in the presence of calcium ions but not in EDTA containing buffer. A calcium ion titration showed half maximal binding at approximately 200 μM Ca2+. The metal ion induced conformational change in the isolated fragment was also studied with affinity purified rabbit antibodies against Gla domainless protein C. Antibodies that bound in the presence of calcium ions and that could be eluted with EDTA recognized the metal ion induced conformational change in the isolated EGF homology domain. Our results suggest that one or both of the EGF homology regions are involved in the Gla-independent high affinity calcium binding in the vitamin K-dependent plasma proteins.
RELATIONSHIP BETWEEN LUPUS ANTICOAGULANTS AND ANTIBODIES TO PHOSPHOLIPID
Authors: Triplett D A , Brant J T , Musgrave K , Orr C A 
Published: August 2018

The relationship of lupus anticoagulants (LA's) to antibodies (IgG and IgM) to cardiolipin (CL), phosphatidylserine (PS), phosphatidylinositol (PI) and phosphatidic acid (PA), detected by an enzyme linked immunoassay, was examined in a series of 100 patients with well characterized LA's. 73% of patients demonstrated antibodies to one or more phospholipids; 62% were positive for CL, 57% were positive for PS, 57% were positive for PI, and 51% were positive for PA. Of the samples with antibodies to phospholipid, 32% had IgG type antibody only, 16% had IgMonly, and 52% had both IgG and IgM antibodies. Of the 100 patients,19% had a history of thrombosis, 8% had ahistory of spontaneous abortion, and 6% had a history of seizure disorder. These complications occurred in the presence (61%) and absence (39%) of detectable phospholipid antibodies. Drug-related LA's were observed in 34 patients; of these 74% were positivefor antiphospholipid antibodies and 24% hada history of thrombosis.The distribution of antibody types with drug-related LA's was similarto the overall group, with 40% IgG only, 8%IgM only and 52% both IgG and IgM These findings indicate that IgG and IgM antibodies to phospholipid are not observed in all patients with lupus anticoagulants, that thrombosis does occur in this population in the absence of detectable antibodies to phospholipid and that drug-related LA's are associated with thrombosis. Furthermore, there appeared to be little relationship between the degree of prolongation of the aPTT and the titer of anti-phospholipid antibody.
PREVENTING VENOUS THROMBOSIS (VT) WITH HEPARIN ALONE OR WITH HEPARIN/DIHYDROERGOTAMINE AFTER ELECTIVE HIP REPLACEMENT, A DOUBLE-BLIND, RANDOMISED, VENOGRAM END-POINT COMPARISON
Authors: Cade J F , Mills K W , Gallus A S , Murphy W 
Published: August 2018

Dihydro-ergotaraine (DHE) appears to be synergistic with small doses of hepari when used to prevent VT after general surgery. However, doubt remains whether DHEhas this effect in patients with elective hip replacement (THR). We have therefore compared the results of VT prophylaxis using sub-cutaneous (sc) low-dose heparinalone or sc heparin plus sc DHE in a double-blind, randomised, study of 126 patientshaving elective THR, 98 at centre (1)and 28 at centre (2).All received 5000 iu sodium heparin, hourly for 7 days, starting 2 hours before surgery at centre (1), or immediately after surgery at centre (2). Patients alsoreceived a separate 0.5 ml (0.5 mg) DHEorplacebo injection each time they receivedheparin. Patients had bilateral ascendingvenography on the 7th postoperativeday, and venograms were read before the treatment code was broken.These results do not support the presence of synergism between heparin and DHE in this situation.