bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diabetes Mellitus Alters the Effect of Peptide and Protein Ligands on Membrane Fluidity of Blood Platelets
Authors: Watala Cezary , Gwoździński Krzysztof , Pluskota Elżbieta , Pietrucha Tadeusz , Walkowiak Bogdan , trojanowski Zygmunt , Cierniewski Czesław S 
Published: July 2018

SummaryThe increased nonenzymatic glycosylation of platelet membrane proteins has been suggested to underlie platelet hypersensitivity in diabetes and the relationship of this to the reduced membrane lipid fluidity has been reported. As the modulation in membrane fluidity may determine the degree of accessibility of membrane receptors, the consequent alterations in membrane lipid-protein interactions in diabetes mellitus may also underlie the differentiated effects of various thrombotic and fibrinolytic agents on platelet membrane lipid bilayer.In the present study we employed electron paramagnetic resonance and fluorescence spectroscopy to explore the ligand-induced platelet membrane fluidity changes in diabetic state, i.e. under conditions when the membrane architecture is considerably altered.The yield of the excimer formation of pyrenemaleimide (PM), which depends directly upon the collisional rate and distances between molecules, was elevated in diabetic platelet membranes, thus pointing to the occurrence of some constraints in the structure/conformation of platelet membrane proteins in diabetes mellitus. Such an immobilization of PM was accompanied by the significant elevation in membrane protein gly-cation in diabetic platelets. The effects of various interacting ligands on platelet membrane fluidity were significantly lower in diabetic platelets, and the differences were much more distinct at the lower depths of a lipid bilayer. Nevertheless, the alterations in membrane lipid fluidity observed upon the interaction of a given ligand occurred with an approximately equal frequency in control and diabetic platelets. Moreover, the probability that these alterations were less profound in diabetic platelets was the same for all types of ligands studied. In diabetic patients the interaction of RGDS and tissue-type plasminogen activator with platelet membranes resulted in much smaller reductions of the h+1/h0 parameters in 5-DOXYL-Ste acid-labelled platelets, thus indicating a lesser rigidization of membrane lipid bilayer in diabetes. Likewise, the fluidizing effect of both fibrinogen itself and fibrinogen-derived peptides containing γ-chain carboxy-terminal sequence H-12-V was less pronounced in diabetic platelet membranes.
Detection of a Hypercoagulable State in Nonvalvular Atrial Fibrillation and the Effect of Anticoagulant Therapy
Authors: Mitusch Rolf , Slemens Hans J , Garbe Michael , Wagner Thomas , Sheikhzadeh Abdolhamid , Diederich Karl W 
Published: July 2018

SummaryThe purpose of the study was to evaluate alterations of the hemostatic system and the effect of anticoagulant therapy in nonvalvular atrial fibrillation. A set of molecular hematologic markers was measured prospectively in 69 patients with atrial fibrillation and 28 age-matched patients in sinus rhythm. Significantly elevated levels of thrombin-antithrombin III complex (8.5 ± 1.6 vs. 2.5 ± 0.3 αg/1; p <0.001), fibrin monomers (27.1 ± 3.2 vs. 13.4 ± 3.7 nM; p <0.001), D-dimers (788 ± 76 vs. 405 ± 46 αg/l; p <0.005), and tissue-type plasminogen activator (9.6 ± 0.5 vs. 7.2 ± 0.5 αg/l; p <0.05) were observed in patients with atrial fibrillation compared to those in sinus rhythm. In a subgroup of patients in whom anticoagulant therapy with oral coumadin or standard intravenous heparin was established after the initial study, hemostatic activation decreased significantly. In conclusion, molecular hematologic markers indicate a hypercoagulable state in atrial fibrillation which may characterize a group of patients at elevated risk for thromboembolic disease.
Phenotyping and Genotyping of Coagulation Factor V Leiden
Authors: Engel H , Zwang L , van Vliet H H D M , Michiles J J , Stibbe J , Lindemans J 
Published: July 2018

SummaryThe currently used activated Protein C resistance test demonstrated to be of limited diagnostic value for the detection of the mutant Factor V Leiden. Moreover, this assay is not useful for patients under anticoagulant therapy. A modification of the APC resistance test, applying Factor V deficient plasma is described which demonstrates a specificity and sensitivity of 1.0. The superiority of the modified APC resistance test over the existing APC resistance test was verified by genotyping.For that purpose, the Amplification Refractory Mutation System (ARMS) was applied to the detection of the G to A mutation at position 1691 in the gene encoding coagulation Factor V. The mutation at that position could be easily detected by using each of two allele-specific oligonucleotide primers concomitantly with one common primer in two separate polymerase chain reactions, thereby amplifying a fragment of 186 base-pairs of the Factor V gene.
Factor V Gene Mutation Is a Risk Factor for Cerebral Venous Thrombosis
Authors: Martinelli I , Landi G , Merati G , Cella R , Tosetto A , Mannucci P M 
Published: July 2018

SummaryTo evaluate the association between coagulation defects and cerebral venous thrombosis, a case-control study was conducted in 25 patients who had no autoimmune, neoplastic or infectious disease and 75 healthy individuals. There were no patients with deficiency of protein C or protein S. Four had resistance to activated protein C (APC) and one had APC resistance associated with antithrombin deficiency. APC resistance was investigated by DNA analysis, and diagnosed by the presence of a point mutation in the factor V gene, which predicts replacement of Arg506 with Gin at one of the two APC cleavage sites in activated factor V. The prevalence of APC resistance was 20% in patients and 2.7% in controls. This difference was statistically significant (p = 0.01) and the odds ratio was 9.1. A circumstantial factor predisposing to cerebral venous thrombosis (such as oral contraceptive intake, pregnancy, puerperium, trauma or prolonged immobilization) was reported in 72% of cases. In conclusion, APC resistance is the most frequent coagulation abnormality associated with cerebral venous thrombosis.
Characterization of a cDNA Encoding Murine Coagulation Factor VII
Authors: Idusogie Esohe , Rosen Elliot , Geng Jie-Ping , Carmeliet Peter , Collen Desirá , Castellino Francis J 
Published: July 2018

SummaryThe cDNA encoding murine coagulation factor VII (mfVII) was isolated and reconstructed from a Λ Zap cDNA library generated from murine liver mRNA. The cDNA contains 1903 nucleotides spanning 15 bases upstream of the 5’-translation initiation codon, an open reading frame of 1338 nucleotides, 550 nucleotides downstream of the first stop codon and a 3’ poly(A) tail. The translation product is composed of a 41-amino acid signal/propeptide region followed by a 405-residue mature protein. The latter is highly homologous to that of human, rabbit, bovine, Rhesus monkey, and canine fVII. All protein domains of hfVII are strictly conserved in mfVII.
Comparison of Two Warfarin Regimens in the Prevention of Venous Thrombosis following Total Knee Replacement
Authors: Francis Charles W , Pellegrini Vincent D , Leibert Kristin M , Totterman Saara , Azodo Michael V , Harris Carl M , Cox Christopher , Marder Victor J 
Published: July 2018

SummaryA prospective, randomized trial was conducted to compare the effectiveness and safety of warfarin given in two regimens in prevention of venous thrombosis after total knee replacement. Adult patients scheduled for primary or revision total knee replacement were randomly assigned to receive either a “two-step” warfarin regimen beginning 10-14 days pre-operatively or, alternatively, to begin warfarin the night before surgery. Post-operatively, the dose was adjusted in both groups to achieve a target International Normalized Ratio (INR) of 2.2 and prophylaxis was continued until venography on post-operative days five through nine. Bleeding was assessed by surgical blood loss, transfusion requirements, changes in hematocrit, and clinically identified bleeding complications. The occurrence of deep vein thrombosis was nearly the same in the two treatment groups, 39% in patients randomized to the two-step regimen as compared to 38% in those beginning the night before surgery. The occurrence of proximal vein thrombosis was also similar, 5% versus 7% (p = NS). Patients in the two-step group received 1.33 ± 1.26 transfusions compared to 0.95 ± 1.22 in the night before group (p <0.05) and also had a lower nadir post-operative hematocrit of 26.7 ± 3.1 as compared to 28.5 ± 3.2 (p <0.0001). Major bleeding complications were associated with excessively prolonged INRs and occurred in five patients in the two-step group and two in the night before group. Patients in both groups who developed thrombosis had a significantly lower INR on post-operative days two and three compared to those without thrombosis. We conclude that a prophylactic warfarin regimen for prevention of deep vein thrombosis after total knee replacement beginning the night before surgery is more convenient and may be associated with less bleeding than a regimen beginning warfarin 10-14 days pre-operatively. Careful control of anticoagulant intensity is needed to achieve maximum effectiveness and avoidance of bleeding complications.
Inhibitory Effect of a Synthetic Prostacyclin Analogue, Beraprost, on Urokinase-type Plasminogen Activator Expression in RC-K8 Human Lymphoma Cells
Authors: Nomura Naoki , Niiya Kenji , Shinbo Masahiro , Ozawa Tetsuo , Hayakawa Yumiko , Higashiyama Ko-ichi , Fujimaki Masao , Sakuragawa Nobuo 
Published: July 2018

SummaryPlasminogen activation by urokinase-type plasminogen activator (uPA)is implicated in tumor invasion and metastasis by the breakdown of extracellular matrix. We have recently demonstrated the inhibitory effect of cAMP on uPA gene transcription in RC-K8 human lymphoma cells (Biochim Biophys Acta 1268: 293-9, 1995). Prostacyclin produced by endothelial cells is shown to increase cellular cAMP levels by activating adenylate cyclase. We, therefore, examined the effect of a stable analogue of prostacyclin, Beraprost, on uPA production in RC-K8 cells. uPA activity gradually increased in the conditioned medium with time. Beraprost (0.1 nM-1.0 μM) inhibited uPA accumulation in a dose-dependent manner without affecting cell viability. Fibrin-zymography demonstrated that high and low molecular forms of uPA were present in the conditioned medium and that after Beraprost-treat-ment all forms of uPA decreased and no PA/PA inhibitor complex was present. Northern blot analysis revealed that after exposure to Bera-prost, uPA mRNA levels increased transiently and then rapidly decreased to below control levels. Treatment with Beraprost resulted in a rapid activation of cellular cyclic AMP-dependent protein kinase (PKA). Beraprost completely negated uPA gene expression induced by phorbol myristate acetate, an activator of protein kinase C (PKC). These results suggest that Beraprost inhibits uPA production by suppressing uPA gene expression through the PKA pathway and that PKA-mediated signals are dominant in uPA gene expression as compared to those medicated by PKC. This inhibition of uPA expression by a prostacyclin analogue may be an important fact to explain the mechanism of anti-metastatic effects of prostacyclin.
Hemostatic Disorder of Uremia: The Platelet Defect, Main Determinant of the Prolonged Bleeding Time, Is Correlated with Indices of Activation of Coagulation and Fibrinolysis
Authors: Mezzano Diego , Tagle Rodrigo , Panes Olga , Pérez Marcos , Downey Patricio , Muñoz Blanca , Aranda Eduardo , Bajra Pliar , Thambo Sergio , González Fernando , Mezzano Sergio , Pereira Jaime 
Published: July 2018

SummarySeveral parameters of primary hemostasis and markers of activation of coagulation and fibrinolysis were measured in 48 patients with severe (creatinine clearance <20 ml/min) chronic renal failure (CRF) without dialysis and diseases or drugs affecting hemostasis. Bleeding time (BT) was prolonged in 25/48 patients, and was correlated with age of patients, severity of renal failure, hematocrit, impairment in platelet aggregation-secretion and decrease in platelet ATP content. Defects in von Willebrand factor played no role in the prolongation of the BT. Multivariate analysis showed that only platelet dysfunction and severity of renal disease were independent predictors of the BT in uremia. The platelet functional disorder was significantly correlated with a reduction in platelet ATP and ADP.High levels of plasma thrombin-antithrombin complexes (TAT), prothrombin fragment F1+2, fibrinogen and factor VIIc were observed in patients with CRF, as described in prethrombotic states. Plasmin-antiplasmin complexes (PAP), fibrinogen and fibrin degradation products (FgDP, FnDP) were significantly increased, and the activity of plasminogen activator inhibitor (PAI-1) was slightly reduced, denoting an activation of fibrinolysis.A negative correlation was found between platelet levels of ATP and ADP with plasma TAT, F1+2 and PAP. Furthermore, plasma PAI-1 activity was negatively correlated with the BT and was lower in patients with prolonged BT as compared with controls and patients with normal BT. These links between primary hemostasis and activation of coagulation and fibrinolysis suggest that increased intravascular generation of thrombin and/or plasmin is an important mediator of the defects in primary hemostasis, prolongation of the BT and, probably, bleeding in CRF.
Antibodies Against Platelet Membrane Glycoproteins: Effect On Ristocetin-Induced Platelet Aggregation
Authors: Ali-Briggs E F , Jenkins C S P , Clemetson K J 
Published: July 2018

Some membrane glycoproteins (GPs) have been isolated by lectin-affinity chromatography and antibodies towards them have been raised. Platelets that have lost glycocalicin no longer respond to ristocetin-human VIII:WF, bovine VIIIR:WF, or to anti-glycocalicin or anti-GPs la and lb antibodies but are still agglutinated by anti-GPs lib and Ilia antibodies. Anti-GPs la and lb and anti-glycocalicin antibodies, IgG and Fab' fragments inhibited ristocetin- human VIIIR:WF- and bovine VIIIR:WF-induced aggregation of fixed, washed platelets and of platelets in plasma while anti-GPs Hb and Ilia antibodies were without effect.Crossed immunoelectrophorectic studies showed that glycocalicin was present on whole platelets in only trace amounts; anti-glycocalicin antibodies, however, recognized a slower migrating component. Platelets incubated in an EDTA-free medium no longer respond to ristocetin-human VIIIRrWF. Membranes isolated from such platelets contained glycocalicin which cross-reacted with a remnant of the slower migrating component. Anti-GPs la and lb antibodies gave more complex patterns but it was possible to identify the slower moving component recognized by the anti-glycocalicin antibodies.These results show that glycocalicin is not normally found as such on whole platelets but is present as a precursor which is most likely GP lb. On degradation of this precursor, glycocalicin is released from the membrane and VIIIRrWF-receptor activity is lost.
Injury Of Cultured Endothelial Cells By Thrombin-Stimulated Platelets
Authors: Jørgensen L , Grøthe A G , Larsen T , Kinlough-Rathbone R L , Mustard J F 
Published: July 2018

Platelets stimulated in vivo may cause endothelial injury. The question is whether a similar effect of platelet stimulation may be shown in vitro.Endothelial cells were cultured from human umbilical veins in Medium 199 with 20 per cent heat-inactivated serum. Semiconfluent cultures, 100-400.000 cells per dish, were labelled with Na2Cr51O4. Twenty-four hours later human platelet suspension (final cone. 200.000 per mm3) and thrombin (final cone. 4 U/ml) were added to the medium and the culture dish shaken for 15 min. The percentage of cells detached from the culture dish and the percentage of Cr51 released from the endothelial cells into the ambient fluid during the shaking were determined and used as parameters of cell injury. Increased percentages of loosened cells and Cr51 into the ambient fluid were observed with platelet suspension and thrombin compared to controls without platelet suspension and/or thrombin. Platelet-free supernatant after reaction of thrombin with platelet suspension had a similar effect. Thrombin alone caused a moderat release of Cr51, but no increased loosening of cells. Both parameters increased with increasing dose of thrombin when the platelet count was kept constant. The percentage of loosened cells increased with increasing platelet number when the dose of thrombin was constant. A significant release of Cr51 occurred only at high concentrations of platelets. Scanning and transmission electron microscopy of endothelial cells exposed to thrombin-stimulated platelets confirmed the presence of loosening and injured cells in association with platelets. The endothelial cells were bulging, intercellular junctions opened up, the plasma membrane on the luminal side showed villi and breaks and the cytoplasm had increased electron density. Thus, platelets stimulated by thrombin may cause injury of endothelial cells also in vitro.
Direct Assay For Factor XII In Plasma
Authors: Zuffi T , Jordan R 
Published: July 2018

A chromogenic substrate assay for FXII in plasma samples has been developed. The method involves 0°C activation of the contact factors with dextran sulfate, and a direct selective measurement of the FXIIa activity generated by hydrolysis of the synthetic substrate S2302 in the presence of the kallikrein inhibitor, soybean trypsin inhibitor. Using these procedures, the kinetics of both FXII and pre- kallikrein activation could be studied and it was found that the relative rates of activation of these two zymogens did not necessarily coincide.When this dextran sulfate treatment of FXII or HMWK-deficient plasmas was tried, insignificant kallikrein or FXIIa activity was generated, demonstrating that contact activation was not occurring. These studies have shown that a dextran sulfate activation can be used as an assay procedure for FXII in plasma and can distinguish normal from certain deficient plasmas.
Protection Of Endotoxin Induced Disseminated Intravascular Coagulation In Rats By Gabexate Mesilate
Authors: Yoshikawa T , Furukawa Y , Murakami M , Takemura S , Kondo M 
Published: July 2018

Gabexate mesilate[ methane sulfonic acid salt of ethyl-p- (6-guanidino hexanoyloxy) benzoate : FOY ] has recently been developed in Japan, and has been known to have potent inhibitory effects on trypsin, kallikrein, plasmin, thrombin and C1-esterase. Advantage of clinical use of this agent is that FOY has smaller molecular weight than aproti- nin so that production of antibody against FOY is hardly observed. In the present investigation, effect of FOY on disseminated intravascular coagulation (DIC) was examined using experimental animal models, in comparison with that of heparin.Female rats of Wistar strain (8-weeks) were infused with l00mg/kg of bacterial endotoxin (Lipopolysaccharide B; E. coli; 055, Difco) continuously for 4 hours through femoral vein. Blood samples were serially taken from abdominal artery using catheter and examined for plasma fibrinogen, FDP, platelet counts, prothrombin time and partial thromboplastin time. After the experiment, kidneys were removed to examine the deposition of fibrin to glomeruli.Different concentrations of FOY were intraperitoneally injected to the rats prior to the infusion of endotoxin, and it was found that the administration of 10 mg/kg of FOY showed the most potent inhibitory effect on the development of DIC, either hematologically or histologically. In comparison, heparin showed a strong inhibitory effect on DIC over a dosage of 5 U/kg.It is concluded that, although inhibitory effect of FOY was less significant than heparin, FOY might be valuable agent for the treatment of DIC especially when heparin is difficult to use in such cases as severe hemorrhagic tendency.
The Effect Of Plasmin On Factor XIII (Fibrin Stabilizing Factor)
Authors: Rider D M , McDonagh J M 
Published: July 2018

The action of plasmin on several blood clotting factors has been studied; however, controversy exists concerning the effect of plasmin on factor XIII. Factor XIII was purified from plasma and platelets and then exposed to plasmin for up to 6 hours. Plasmin to factor XIII ratios ranged from 0.03-0.1 casein units plasmin per mg factor XIII. These plasmin levels exhibited strong proteolytic activities against B-casein and purified human fibrinogen Following incubation of factor XIII (activated and unactivated) with plasmin the mixtures were electrophoresed on 7% SDS-polyacrylamide gels. The factor XIII preparations were assayed for 14C-putrescine incorporating activity before and after exposure to plasmin. Platelet factor XIII was,labeled With 125Iodine and lableled a subunit (activated and unactivated) was exposed to plalmin for up to 2 hours. These mixtures were electrophoresed on 12.5% Urea-SDS Polyacrylamide gels and a radioactivity profile was determined for each gel.Following extensive exposure to Plasmin the relative molecular weights of the factor XIII subunits (a, a* and b)remained constant and almost all (90-100%) of the 14C-put-rescine incorporating activity was recovered. The radio-activity profiles of the gels of 125I-labeled platelet factor XIII were identical before and after incubation with plasmin. Plasmin did not activate factor XIII in the assay system nor did factor XIII inactivate plasmin by crosslinking it. These experiments indicate that plasmin does not activate or degrade factor XIII and that the b subunit of plasma factor XIII plays no role in protecting the a subunit from the action of plasmin.
Overview: Reaction To Two Types Of Thrombus Deposition
Authors: Moore S , Belbeck L W , Richardson M 
Published: July 2018

Damage to the luminal surface of an artery is associated with the development of platelet-fibrin thrombus or a monolayer of platelets. The first type of reaction (Type I) follows damage caused by an indwelling catheter or by repeated exposure of the endothelial surface to antibody. The second (Type 2) follows removal of the endothelium by a Fogarty balloon catheter. The reaction of the vessel wall to these two types of injury, while having many similar features, differs in a number of important respects. Both are dependant on the interaction of platelets with the vessel wall and can be suppressed or inhibited by inducing a severe thrombocytopenia using anti-platelet serum. In both, the thickness of lesions is related to repetitiveness of injury. Both are characterized by smooth muscle cell proliferation and lipid accumulation in normolipemic rabbits. The type I lesion regresses rapidly, losing size and lipid content, when the injury stimulus is removed. The Type 2 lesion persists and continues to accumulate lipid over timeIn the Type I lesion, induced by an indwelling aortic catheter, platelet consumption is increased for eight days and fresh platelet-fibrin thrombus may be found on the surface of the lesion months after placement of the catheter. Platelet survival is shortened. In the Type 2 lesion the initial interaction of platelets with the vessel wall is short lived, and the surface covering of platelets is rapidly lost. Platelet survival is not shortened in rabbits. While both lesions exhibit abundant accumulation of extracellular and intracellular lipid, this occurs earlier in the Type I lesion and disappears fairly rapidly when the Injury stimulus is removed. Lipid appears later in the Type 2 lesion, persists and increases in amount, even following a single injury. Fatty streaks, though observed in both types of injury, are more likely to be seen as a stage of regression of Type I lesions. The Type I lesion closely resembles the raised (complicated) lesion of human atherosclerosis. The Type 2 lesion resembles the human fibrous plaque. Supported by Grants MT-2168, M.R.C., 15-7 O.H.F.