bluuebunny/crossref_metadata_2025_split huggingface dataset:
PLATELET RELEASE DURING EXERCISE IN PACEMAKER PATIENTS
Authors: Myreng Y , Gjesdal K , Kjeldsen S E , Lande K , Eide I , Grendahl H 
Published: August 2018

Seven pacemaker patients with complete AV-block were studied during one to three week periods of either ventricular (VVI), or atrio-ventricular pacing (DDD) or triggered ventricular pacing (VAT)At rest, the plasma p-thromboglobulin (BTG), arterial adrenaline and nor-adrenaline as well as atrial rate were not significantly different during standard and physiological pacing. Following ergometer bicycling, BTG increased significantly (p <0.004), and more so in VVI pacing (from 38 ±15 to 73 ±15 ng/ml) compared to DDD (27 ±6 to 44 ±13),p<0.05. Arterial plasma adrenaline at baseline was 60 ±27 in VVI and 58 ± 27 pg/ml in DDD, with increases during exercise to 353 ±197 and 338 ±164 respectively. Neither was any noradrenaline cone significantly different: 253 ±74 to 2962 ±2031 in VVI versus 226 ±143 to 2848 ±2032 during DDD at rest and during exercise, respectively. The atrial rate was 73 ±11 at baseline increasing to 125 ±15 ppm, versus 69 ±12 to 127 ±15 ppm (ns). Physiological pacing is thus associated with lower platelet release at baseline (ns,p<0.07) and exercise (p<0.05), despite no significant difference in arterial catecholamine concentration or the related atrial rate. Increased blood turbulence during atrio-ventricular asynchrony may contribute to the increased release in VVI-pacing
ASPIRIN EFFECT ON PLATELET ANTIPLASMINS PRELEASE
Authors: Woods A I , Lazzari Ji A 
Published: August 2018

It was shown platelet antiplasmin activity which is released by col 1anen(Col)and thrombin, probably associated with a-oran u 1 es . Lys i s area produced by eunl obul i ns (eun) of PPP and PRP whether or not previously treated with ADP(5uM), Col(20ug/ml) and aspirin(ASA)(00up/nl)in plas-mi nooen- f ree-f i bri n plates were s tudi ed. Res u 1 ts (mm2 ) were:eunPPP:151.3±39.8;+ADP:155.7±47;+Co1: 155.5±150.8;
+ ASA: 160±142. -EugPRP: 142*42;+ADP: 145*72;+Col : 136*43 ; -⋋ASA: 138+47.-EugPRP produced slightly lower lysis area than euaPPP(p:ns).ADP , Co 1 and ASA neither modify the lysis area of eugPPP nor of eugPRP.Washed piatelets(WP)whether or not treated with ASA were resuspended in eu^PPP and then treated with Co 1 ( 2 and 20ug/ml ). Resul ts (mm2 )were : euoPPP:109.8+35;+3xl05WP/ul:66.4±24;+106WP/u1:63±17;+2x lO WP/ul:58.4±13.- Wi th Col(20ug/ml):euoPPP:101.3±28;
+ 3xl05WP/ul:48.4±14; + 10cWP/ul :46.2±16;+2xl06WP/ul :44.5± i2;+ 2x106WP/u1+ ASA:45.2±8.-With Col(2ug/nl):eugPPP:10 3± 25;+2xl06WP/ul : 49±10 ;+2x1 Of>WP/ul+AS A: 50 . 9±13 . WP in eug PPPshowed lower lysis area than eugPPP(d<0.00 1). The higher number of piatelets ,the lower lysis area.Col-treated WP showed greater inhibition of lysis area than non-treated WP.ASA could not inhibit this effectConclusion:In euoPRP there was a slioht antiplasmin activity related with platelets not comoletely eliminated from eug fractionation.WP in euoPPP showed hioher antiplasmin activity.High and low doses of Col produced antiplasmin release.ASA could not inhibit its release with both doses of Col.We must consider the possibility that platelet antiplasmins could be released by different metabolic pathways other than cycl oox.ygenase way or they are not stored in the a-granules.
ANALYSIS OF THE FUNCTIONAL ROLE OF PLATELET MEMBRANE GLYCOPROTEINS WITH MONOCLONAL ANTIBODIES
Authors: Nagata H , Nomura S , Oda K , Kokawa T , Yasunaga K 
Published: August 2018

Eight monoclonal antibodies were obtained which recognized platelet surface antigens of these, 5 (NNKYl-32, NNKY2-5, NNKY2-6, NNKY2-11, NNKY2-18 ) recognized GP IIb-IIIa complex, 2 (NNKY5-4, NNKY5-5 ) recognized GP lb and 1 (NNKYl-19) recognized CD 9 antigen. They were used to research the platelet membrane antigens.Monoclonal antibodies that recognize CD 9 antigen, which exists on the surface of platelets, acute lymphoblastic leukemia cells, eosinophils and other tissue, are known to act as an aggregating agent to platelets and NNKYl-19 was fond to induce platelet aggregation accompanied by ATP release. NNKY5-4 had no effect on platelet functions. NNKY5-5 inhibited aggregation induced by ristocetin but had no effect on aggregation induced by ADP, collagen, thrombin, and NNKYl-19. NNKYl-32, 2-5, 2-6, 2-11, and 2-18 inhibited aggregation induced by ADP, collagen, thrombin, and NNKYl-19, although slight release of ATP was recognized when NNKYl-19-induced aggregation was completely inhibited by NNKYl-32. Mutual inhibition of binding to platelet membranes between the 3 groups of monoclonal antibodies was not recognizedNNKYl-19-induced aggregation was associated with a lag time that was plo-longed in inverse proportion to antibody concentration. Aspirin had almost no effect on NNKYl-19-induced aggregation. A TXA2 receptor antagonist, a calci-um-channel blocking drug and EDTA inhibited NNKYl-19-induced aggregation. These results indicate that GP I b, GP IIb-IIIa complex and the cyclooxygenase pathway are not involved in NNKYl-19-induced platelet activation, that the target of NNKYl-19 on the platelet membrane is same as that of TXA2, and that the mechanism of activation by NNKYl-19 is related to calcium flux.
PLATELET ACTIVATION INDUCED BY A MONOCLONAL ANTIBODY AGAINST THE PLATELET GP Ilb/IIIa COMPLEX
Authors: Modderman P W , Huisman J G , van Mourik J A , Kr A E G , Borne v d 
Published: August 2018

A receptor for fibrinogen on the platelet GP Ila/lIIb complex is induced by ADP, thrombin and other agonists. To study functional domains on GP Ilb/IIIa, the effects of anti-GP Ilb/IIIa monoclonal antibodies (Mab’s) on platelet function were determined. One of these Mab’s, 6C9, induced platelet aggregation. The antibody binds to the intact GP Ilb/IIIa complex only, not to free GP lib or free GP Ilia. Its epitope is different from that of C17, a Mab that inhibits ADP-induced fibrinogen binding and platelet aggregation. 6C9 induces fibrinogen-mediated aggregation rather than agglutination since 6C9-induced platelet interactions were blocked by treatments that also inhibited the effects of ADP etc., without inhibiting binding of 6C9 itself. 6C9 induces binding of 125I-fibrinogen (35.000 ± 7.300 molecules/platelet, Kd = 1.3 ± 0.4 µM) to unstirred platelets. Binding of fibrinogen was 60 to 80% inhibited by apyrase, which indicates that 6C9-induced fibrinogen binding is largely mediated via ADP released from platelets. In addition, 6C9 induced aggregation of platelets in the absence of extracellular fibrinogen. Mediation of this process by platelet fibrinogen or other a-granule proteins, released upon activation by 6C9, was implicated by the finding that aggregation of washed platelets, but not of platelets to which fibrinogen was added, could be blocked by PGI2. Platelet release was also assessed directly by measuring β-thromboglobulin (α-granules) and (14C) serotonin (dense granules) in the medium of unstirred platelets incubated with 6C9. F(ab')2 fragments of 6C9 only aggregated platelets in the presence of fibrinogen and did not release (14C) serotonin. Moreover, release induced by intact 6C9 was inhibited by anti-GP Ilb/IIIa Mab C17 but not by C17 F(ab’)2, although the latter inhibited ADP-induced platelet aggregation. These data indicate that binding of antibodies to specific sites on GP Ilb/IIIa may induce Fc-dependent platelet activation.This study was supported by the Foundation for Medical Research MEDIGON (grant no. 900-526-057.
THE ROLE OF THE GP IIb/IIIa COMPLEX AND vWF IN PLATELET -COLLAGEN INTERACTION
Authors: Andreas Ruf , Morgenstern Eberhard , Patscheke Heinrich , Santoso Sentot , Müller-Eckhardt Christian , Heimburger Norbert 
Published: August 2018

Our recent studies showed that collagen fibrils (CF) are internalized by platelets in citrated plasm. This phenomenon was not observed in EDTA-PRP. In order to investigate whether collagen internalization is mediated by a receptor we studied the effect of monoclonal antibodies against the receptor molecules GP IIb/IIIa (Gi5) and GP Ib (AN51, Da-kopatts GmbH, Hamburg). Washed human platelets from healthy donors were incubated with lOμg of Gi5 or 4μg of AN51 per ml of platelet suspension (2 × 108 platelets per ml). After 10 min. at 37° C we added AOpg collagen (Hormonchemie, München) per ml of platelet suspension. After an additional incubation period of 10 min. the reaction was stopped by glutaraldehyde fixation (40μl of a 3% glutaraldehyde and of a 0.2 % tannin solution in phosphate buffer). To investigate the role of vWF in the internalization process we added 1Oμg/ml ferritin-labeled anti-vWF Fab-fragments to the platelet suspension two min. in advance of collagen stimulation (40μg/ml; 10 min). The values in percent of the inhibition of the internalization phenomena were obtained by statistical evaluation of these phenomena observed on ultrathin serial sections. Washed platelets interacted with CF in the same manner as platelets in citrated plasm, but aggregates were only formed after stirring. Washed platelets which had internalized CF were found to be completely degranulated in contrast to platelets which had only contacted CF without internalization. These platelets were hardly degranulated. The membrane system containing the internalized CF surrounded the contractile sphere of the platelets and always displayed an opening to the platelet surface.We found that Gi5 inhibited collagen internalization up to 95% and anti-vWF to approximately 50%, whereas AN51 showed no effect on this process. Futhermore, Gi5 inhibited the platelet function aggregation and the release reaction which was enhanced by CF internalization. These findings show that the GP Ilb/IIIa complex is strongly involved in the internalization of CF by platelets and suggest an involvement of vWF released from the stimulated platelets in this process by binding to the GP Ilb/IIIa complex.Supported by DFG, Grant MO 124/2-4
REVERSIBLE EXPOSURE OF BINDING SITES FOR FIBRINOGEN ON PLATELET MEMBRANE GLYCOPROTEIN IIB-IIIA
Authors: Akkerman J W N , Mommersteeg M E 
Published: August 2018

When human, gel-filtered platelets are stimulated with Platelet Activating factor (PAF, 500 nM) in the presence of 1 μM 125I-fibrinogen (*F) 15.360 ± 4.850 (n = 5) mol*F bind per platelet after 10 min incubation at 22°C. Under similar conditions 10 μM adrenaline and 10 μM ADP induce the binding of 17.020 ± 4.550 and 20.500 ± 3.910 mol*F/platelet, respectively. Stimulation with PAF in the absence of fibrinogen followed by addition of *F at different intervals (Δt) thereafter, reveals an exponential decrease in bound *F reaching 29 ± 8% of initial binding at Δt = 30 min. Similar patterns are seen with ADP and adrenaline. This decrease is enhanced by raising cyclic AMP (5 μM forskolin) or reducing the cell's energy supply (30 mM deoxyglucose - 1 mM CN- ). Thus, exposed binding sites disappear in the absence of fibrinogenFollowing a first stimulation (with PAF; *F absent), a second stimulation (ADP or adrenaline; *F present) restores the binding to the range found with the second stimulator under optimal conditions. Thus, following a first disappearance of accessible binding sites a second type of binding can be inducedRepeated stimulation with different agonists (PAF-A t-adrenaline-Δ t-ADP- Δ t-collagen, 5 μg/ml) induces repeated exposure and disappearance of binding sites without exhaustion of accessible binding sites. Re-exposure of binding sites is complete with adrenaline and ADP as second and third stimulator, whereas collagen induces 60-70% of the first binding induced by PAF. When the 10 min incubation with *F is increased to 60 min, re-exposure results in binding of 40.000-50.000 mol*F/ platelet, which is close to the number per platelet of glycoprotein IIb-IIIa complexes, the binding sites for fibrinogenThese data support the concept that exposure and disappearance of fibrinogen binding sites is a reversible process and that the maintenance of the exposed state is under tight metabolic control
EFFECT OF FIBRINOGEN RECEPTOR BLOCKERS ON HUMAN PLATELET AGGREGATION, ATP SECRETION AND THROMBOXANE B2 PRODUCTION
Authors: Kerry R , Findlay V , Ambler J , Wallis B J 
Published: August 2018

The sequences of those parts of fibrinogen involved in the binding of fibrinogen to activated platelets are known and mimetics of these sequences, namely Fib(γ)402-411 and Fib(Aα)572-575 are selective fibrinogen receptor blockers. By competing with fibrinogen, these agents prevent the platelet: fibrinogen interaction and hence represent agents capable of selectively preventing platelet:platelet interaction (i.e. aggregation). In the experiments described here these peptides are used as tools to elucidate the interdependence of platelet aggregation, secretion and thromboxane (TxB2) production using a range of aggregating agentsBoth peptides gave quantitatively similar results but Fib(Aα)572-575 was ten times more potent than Fib(γ)402-411. The results are summarised in the table:Experimentally aggregation and secretion were measured simultaneously in a lumi-aggregometer. Thromboxane B2 was subsequently determined by RIA in the same samples. The concentration of Fib(γ)402-411 (ImM) and Fib (Aα)572-575 (100 μM) employed were those that gave half maximal inhibition of an aggregatory response.The results show that a) PAF induced thromboxane production and ATP secretion are dependent on platelet aggregation, b) collagen induced ATP secretion is dependent on platelet aggregation while thromboxane production is independent of aggregation and c) thrombin induced ATP secretion and thromboxane production can both occur independently of platelet aggregation.These observations throw further light on the interdependence of platelet responses and show fibrinogen receptor blockers to be true anti-aggregatory agents.
A NEW MONOCLONAL ANTIBODY TO PLATELET MEMBRANE GLYCOPROTEINIV: EXPRESSION OF GLYCOPROTEIN IV ON PLATELETS, MEGAKRYOCYTES AND ERYTHROBLASTS
Authors: kariyone S , kambayashi H , satoh T , uchida T , ohto H , maeda H 
Published: August 2018

A New monoclonal antibody, designated as TP85, was produced by fusion of the X63.Ag8.653 murine myeloma cell line with splenocytes from BALB/C mice immunized with washed human platelets. TP85 monoclonal antibody precipitated a single petide of 97,000 daltons in both reduced and nonreduced states by immune precipitation of 125I-labelled solubilized membrane. An isoelectric point was around pH 5.0. The antibody was IgG2b in isotype, as determined by the Ouchterlony immunodiffusion method.The reactivity of TP85 was examined by using indirect immuno-fluorescent assays and ABC immunoperoxidase method. TP85 reacted with platelets, megakaryocytes and erythroblasts from normal human and patients with myeloproliferative disorders, but not with lymphocytes, granulocytes and other bone marrow cells. In a panel of cultured cell line, only 5-10% cells of K652 myeloid/ erythroid cell line were positive, but other cell lines, including common ALL(Reh), T lymphoid(Molt-3, CCRF-CEM), B lymphoid(Raji ,Daudi), myeloid(KG-l, HL-60) and monoblastoid(U937, THP-l) cell lines, were all negative.TP85 did not inhibit platelet aggregations induced by ADP, collagen, epinephrine and ristocetin while TP80 which was an antibody for GPIIb/IIIa inhibited these aggregations except induced by ristocetin.It is concluded that glycoprotein IV, which is immunoprecipitated by TP85, may exist not only on platelet membrane, but also on megakaryocytes and erythroblasts, and has no role on platelet aggregation.
MEGAKARYOCYTIC ORIGIN OF PLATELET HLA CLASS I ANTIGEN
Authors: Kieffer N , Titeux M , Henri A , Breton-Gorius J , Vainchenker W 
Published: August 2018

The existence of HLA class I antigens on human platelets is well established. However, several authors have suggested that platelet HLA antigens are not integral membrane components but are acquired from soluble plasma sources and adsorbed to the platelet surface.In the present study, we used the monoclonal antibody W6/32, directed against a monomorphic epitope of the HLA class I antigen for the immunochemical characterization of platelet HLA. Immunoprecipitation experiments, performed after in vitro metabolic radiolabeling of human platelets revealed a band of molecular weight 44,000 identical to that precipitated from metabolic labeled U937 or HEL cells. When the same antibody was tested by indirected immunofluorescence in a double labeling technique on in vitro cultures of human megakaryocytes, performed in the absence of human serum in the culture medium, megakaryocytes identified by an anti-vWF MoAb revealed a membrane staining with W6/32 identical to that observed on other bone marrow cells, e.g. macrophages. Our results provide evidence that platelet HLA has a megaka-ryocytic origin and that residual biosynthesis of HLA antigen does still occur in circulating platelets. However, our results do not exclude the ability of human platelets to adsord circulating HLA class I antigen from plasma.
LUMI-AGGREGOMETER STUDIES OF THE INITIAL ATP-SECRETION FROM COLLAGEN-ADHERENT PLATELETS
Authors: Malmgren R 
Published: August 2018

We have earlier, with the use of a lumi-aggregometer and sub-aggregating doses of collagen (0.2-0.8 ug/ml PRP), been able to detect the initial, aspirin-insensitive secretion of ATP from the collagen-adherent platelets, and to correlate this secretion to the doses of collagen, and onset and degree of subsequent shape change of non-adherent platelets (Malmgren, Thromb Res 4:445, 1986). The present study shows, that 200 ATU of hirudin,which reduced near-maximal aggregation and ATP-secretion induced by high collagen doses (2.5 ug/ml PRP) from 3.35 ± 0.2 uM to 2.85 ± 0.1 uM, did neither reduce the secreted amount of ATP that were 82.5 ± 15 nM in control samples and 90 ± 27.5 nM in hirudin-treated samples, nor reduce platelet shape change when platelets were challenged with 0.31 ug collagen /ml PRP. (200 ATU hirudin completely abolished an equal degree of platelet shape change induced by 0.01 U thrombin). Assuming that 3 % of the platelets in PRP were actually adhering to the collagen fibrils, the secreted amount corresponds to 14.6 ±0.04 pmoles ATP/106adheringplatelets, amounts which closely represented 100 % of their dense granule content. The finding confirms that hirudin does not inhibit platelet adhesion and also indicates, that thrombin-mediated activation of secretory pathways appears not to be involved during the initial phase of platelet-collagen interactions.Dipyridamole (DPA) and dibutyryl cAMP (DBcAMP) inhibited ATP-secretion and platelet aggregation in a dose-dependent manner at high collagen concentrations, but only DBcAMP caused a dose-dependent reduction of ATP secretion (IC50 =10-4 M) induced by sub-aggregating doses of collagen. DPA was devoid of effect in this respect and thus did not inhibit platelet adhesion.Yohimbine, dihydroergotamine and phentolamine reduced ATP-secretion induced by sub-aggregating collagen doses in the mentioned rank order of potency, and with IC50 values in the micromolar range. Ketanserin, ritanserin and propranolol were devoid of effect. The findings suggest that the initial collagen-plate-let interaction involve alfareceptor-mediated mechanisms that may encompass adhesion, while DBcAMP probably interacts with secretory mechanisms connected to phosphatidylinositol turnover.
A SENSITIVE ENZYME-LINKED IMMUNOSORBENT ASSAY(ELISA) FOR SERUM LAMININ
Authors: Sugihara T , Takamatsu J , Kamiya T , Saito H , Kimata K , Kato K 
Published: August 2018

Laminin, a large glycoprotein, is a major and specific component of basement membrane. There were little or no circulating laminin in normal persons, although some recent reports have showed increased values in various diseases(ex. diabetes mellitus and liver disease) by a radioimmunoassay(RIA) using laminin fragment. The minimum detectable sensitivity of RIA was reported to be 20 ng/ml of serum sample. We describe here a more sensitive immunoassay system, and also the concentrations of laminin in sera from healthy subjects and patients. A sandwich ELISA method for measurement of laminin was established by use of purified antibodies to mouse laminin. The assay system consisted of poly-stylene balls with immobilized antibody F(ab’)2 fragments and the same antibody Fab1 fragments labeled with β-D-galactosidase from E.Coli. The assay was highly sensitive and can detect as small as 0.5 ng/ml of serum laminin.Coefficients of variation in within-run and between-run precision studies for serum laminin were good. Serum laminin levels in healthy subjects of various ages ranged from 1.5 to 3.9 ng/ml(n=60). Fifty eight patient sera (collagen disease(n=18), hepatic disease(n=20), and renal disease (n=20)) were examined. Significant differences between the normal sera and 3 diseases sera were observed as shown belowIt is concluded that circulating laminin apparently exists in normal persons and there are higher laminin level in some diseases which appears to involve basement membrane-rich organ
STUDIES ON SMALL MOLECULAR WEIGHT ADHESION PROTEINS (SAPs) FROM CONNECTIVE TISSUES
Authors: Wasi S , Alles P , Gauthier D , Bhargava U , Farsi J , Aubin J E , Sodeki J 
Published: August 2018

We have identified a family of low molecular weight proteins with cell attachment properties in a variety of soft and mineralised connective tissues (Wong et al., Biochem. J. 232, 119, 1985). For further characterisation of these proteins we extracted porcine bones with 4 M guanidine hydrochloride and purified the proteins on a series of gel filtration columns The purifed SAPs comprise three bands with Mr -14 000 -17 000. All three proteins bound to heparin-sepahrose in both the presence and absence of 4M urea, and when eluted with 2 M NaCl they retained their cell binding capacity. These proteins promoted the adhesion and spreading of a variety of cell types, including normal fibroblasts, osteoblasts, and epithelial cells, and tumour (osteosarcoma) cells. On Western blotting SAPs did not cross-react with antibodies against fibronectin, laminin or type I collagen; however, they were recognised by a monoclonal antibody to human vitronectin, a polyclonal antibody to bovine vitronectin and polyclonal antibody to human somatomedin B. Dose response experiments indicated that maximum attachment of human gingival fibroblasts occurred in the presence or absence of fetal bovine serum on wells precoated with 2.5 μg/cm2 of SAPs. Attachment of cells to these proteins was partially inhibited by the synthetic pentapeptide Gly-Arg-Gly-Asp-Ser. Utilising the nitrocellulose cell binding assay of Hayman et al (J. Cell. Biol. 95, 20, 1982), the cell attachment to these proteins could be completely inhibited by heparin (100 units/mL) whereas up to 1000 units/mL of heparin had no inhibitory effect on cell attachment to fibronectin and vitronectin. The occurrence of these proteins in a variety of connective tissues and their recognition by different cell types may reflect their general biological role in adhesive mechanisms in both hard and soft connective tissues. Currently, we are investigating the relationship between SAPs and vitronectin, since it is possible that SAPs represent a tissue-processed form of vitronectin or may be novel attachment proteins with regions of homology with vitronectin