bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of Thrombocytopenic Petechiae by Exogenous Serotonin Administration
Authors: Sweetman Harold E. , Shepro David , Hechtman Herbert B.
Published: April 2009

The effect of serotonin on vascular fragility, visible as petechiae, was examined in antiplatelet serum-induced thrombocy topenic hamsters. Serotonin was administered intravenously or intraperitoneally, and following a single injection of 0.5 mg/l00 g body weight, a temporary inhibition of petechial formation for approximately 1 h was observed. Repeated serotonin injections maintained animals free of petechiae for the 4-hour period of administration. Plasma levels of serotonin and the effect of serotonin on cutaneous perfusion were not significant factors in the observed inhibition of petechiae. The data suggest that in normal animals platelet serotonin may contribute more to maintaining microvascular structural integrity than platelet adhesion.
Adenosine Uptake and Deamination by Blood Platelets in Different Mammalian Species
Authors: Doni Gabriella
Published: April 2009

Citrated, platelet-rich plasma from human, guinea-pig and rat blood was incubated at 37 °C with (8-14C)-adenosine at different concentrations (1, 3, 30, 100 µM) with continuous stirring. Nucleotides and nucleosides were separated by high voltage electrophoresis for 1 h in 0.05 M citrate buffer pH 4.5. The spots were eluted and radioactivity was counted. Labelled adenosine was taken up by platelets within a few seconds and radioactivity increased with time of incubation. Guinea-pig platelets incorporated labelled adenosine more slowly than the platelets of other species: after 3 min of incubation with 1 µM (8-14C)-adenosine, 43% of the total radioactivity was found, whereas human and rat platelets incorporated 73 and 72% of the total radioactivity, respectively. The kinetics of incorporation and of nucleotide formation by the enzyme adenosine kinase indicated that the Km was 72.46 µM and the Vmax was 0.85 µM/min in guinea-pig platelets; the Km was 5.06 µM and the Vmax was 00.14 µM/min in human platelets; the Km was 13.72 µM and the Vmax was 0.74 µM/min in rat platelets. The kinetics of deamination and nucleoside formation by adenosine deaminase indicated that the Km was 28.21 µM and the Vmax was 3.22 µM/mm in guinea-pig platelets; the Km was 26.40 µM and the Vmax was 1.41 µM/min in human platelets, but the Km was 60.25 µM and the Vmax was 1.49 µM/min in rat platelets. It was concluded that there is no correlation between the inhibitory activity of adenosine on ADP-induced aggregation in the various species and the rate of labelled adenosine incorporation or deamination.
Clinical and Experimental Evaluation of the Thromboprophylactic Effect of Hydroxychloroquine Sulfate after Total Hip Replacement
Authors: Johansson Evald , Forsberg Krister , Johnsson Hans
Published: April 2009

The rate of postoperative deep vein thrombosis was studied by the 125I-fibrinogen method in 35 patients after total hip replacement. 12 out of 18 patients treated prophylactically with hydroxychloroquine sulfate developed deep vein thrombosis compared with 11 out of 17 patients in the control group. Platelet aggregability was inhibited in vitro by high concentrations of hydroxychloroquine sulfate, but these concentrations were not obtained in vivo and platelet aggregation was not inhibited in patients treated with hydroxychloroquine sulfate (Plaquenil®).
Antithrombin III versus Prothrombin in Liver Cirrhosis
Authors: Aurousseau M.H. , d’Angeli J.L. , Josso F.
Published: April 2009

In patients with liver cirrhosis, a close relationship was observed between the respective levels of antithrombin III and prothrombin, both below 50% in 20 out 27 patients. The absence of any thrombotic complication, despite low plasma antithrombin III, suggests that the preserved balance between the inhibitor and the zymogens of the inhibited enzymes could have a protective effect against thrombotic tendency.
Platelet Phospholipids in Thrombocytosis due to Myeloproliferative Disorders
Authors: Breuer Judit H. , Harsányi Veronika , Solti Veronika , Hollán Susan R.
Published: April 2009

Platelet phospholipids were analyzed in patients with thrombocytosis due to myeloproliferative disorders and secondary thrombocytosis. A significant increase of phos-phatidylcholine together with a decrease of sphingomyelin was observed in each of the 8 patients with primary thrombocythaemia and in each of the 5 patients with excessive thrombocytosis due to primary polycythaemia. The phospholipid pattern of the 3 patients with secondary thrombocytosis did not differ from that of the normal controls. This marked difference in the platelet phospholipids may be helpful in distinguishing secondary thrombocytosis persisting for a prolonged period of time after splenectomy from previously Unrecognized primary thrombocythaemia unmasked by splenectomy. The decreased sphingomyelin/lecithin ratio of platelets in primary thrombocythaemia may interfere with platelet function by increasing the fluidity of their membrane.
Platelet Abnormalities in Thermal Injury
Authors: Hourdille P. , Bernard P. , Belloc F. , Pradet A. , Sanchez R. , Boisseau M.R.
Published: April 2009

A study on platelets was done in 13 patients with severe burns during the period immediately following the thermal injury. For each patient it is possible to define a period, usually beginning around the 8th day postburn, characterised by decrease of ADP and 5-HT in the platelets and by an increase in the ATP/ADP ratio. These abnormalities strongly suggest an acquired storage pool disease. Study of the dense bodies by mepacrine labelling during this period suggests that the platelets release their contents but retain the structures labelled by mepacrine.
The Effect of Sulphinpyrazone and Its Metabolites on Platelet Function in vitro and ex vivo
Authors: Pay Graham F. , Wallis Robert B. , Zelaschi Daniela
Published: April 2009

The thioether metabolite of sulphinpyrazone is between 8 and 13 times more potent than the parent compound as a competitive inhibitor of human, guinea pig and rabbit platelet aggregation induced by sodium arachidonate. Of the other known metabolites, the sulphone is approximately equipotent and the p-hydroxy compounds are much less potent that sulphinpyrazone itself. Malondialdehyde biosynthesis from sodium arachidonate by washed human platelets and collagen-induced aggregation of all three species is also inhibited by the thioether. It is 10 times more potent than sulphinpyrazone. ADP-induced aggregation is not affected by sulphinpyrazone, its thioether metabolite, nor the other metabolites. After intravenous administration of the thioether metabolite to groups of guinea pigs the inhibitory effect on sodium arachidonate-induced platelet aggregation ex vivo was long lasting (up to 24 h). In view of the recent information about the metabolism of sulphinpyrazone to its thioether in guinea pigs, we conclude that the thioether metabolite is the substance responsible for the prolonged effect of sulphinpyrazone on platelet function in this species and in man.
Plasma Concentration of Platelet-Specific Proteins and Fibrinopeptide A in Patients with Artificial Heart Valves
Authors: Dudczak R. , Niessner H. , Thaler E. , Lechner K. , Kletter K. , Frischauf H. , Domanig E. , Aicher H.
Published: April 2009

β-Thromboglobulin (βTG), platelet factor 4 (PF4), fibrinopeptide A (FPA), lactic dehydrogenase (LDH), and platelet count were evaluated in patients with bioprostheses and prosthetic heart valves. βTG and PF4 were significantly elevated in both patient groups (p < 0.001), whereas FPA was normal. There was no significant difference in plasma concentrations of βTG and PF4 between patients with prosthetic heart valves and bioprostheses. LDH levels were significantly (p < 0.001) higher and platelet count lower (p < 0.001) in patients with prosthetic cardiac valves. The data indicate that bioprostheses do not cause haemolysis or activation of the coagulation system. The findings that the plasma concentration of platelet-specific proteins were elevated, support the assumption that both types of valves cause platelet damage.
Characterization of Cryofibrinogen Isolated from Patients’ Plasma
Authors: Stathakis N.E. , Karamanolis D. , Koukoulis G. , Tsianos E.
Published: April 2009

The cryofibrinogen of 27 patients was studied by SDS-polyacrylamide gel electrophoresis and immunochemical methods. Electrophoretic analysis of the isolated cryofibrinogens, as well as the proteins left after heat or thrombin defibrination, showed that cryofibrinogen is composed of two proteins, fibrin(ogen) and cold-insoluble globulin (CIg). A proportion of the fibrin(ogen) component formed stabilized oligomers interlinked through γ-γ dimerization. The degree of fibrin(ogen) proteolysis, as judged by measuring the α: γ ratio of the reduced samples, was very similar to that of the fibrinogen of the original plasma. The CIg:fibrin(ogen) molar ratio in the cryofibrinogens was 0.041 ± 0.018. The CIg and the fibrin(ogen) content of the cryofibrinogens were strongly correlated with the plasma CIg levels.
Natural Inhibitors and Fibrinogen/Fibrin Degradation Products in Patients with Myocardial Infarction
Authors: Engel Araceli M. , Finkelstein A.E.
Published: April 2009

The activity of the inhibitor of activated Stuart factor (anti-Xa) was evaluated together with the activity of the antiactivator of plasminogen (antiplasminogen) and the amount and nature of the fibrinogen/fibrin degradation products (FDP), as indicators of the existence of the risk for hypercoagulability in patients with acute and recent myocardial infarction (AMI and RMI, respectively). The activity of anti-Xa was diminished in the AMI group with a p < 0.001. The antiplasminogen activity was increased in both groups with a p < 0.001; on the other hand, the amount of FDP was increased in the AMI patients and they were of the ‘early’ type, while in the RMI group the increase was not as marked, but the FDP were of the ‘late’ type. In both groups the euglobulin lysis time was very prolonged, while the plasminogen did not vary significantly. The tests described appear to be valuable tools for studying the status of the cardiovascular system during cardiac rehabilitation.
Isolation and Some Characteristics of Urokinase Inhibitors Isolated from Pig Leucocytes
Authors: Kopitar M.
Published: April 2009

Two inhibitors of urokinase were isolated from the extracts of the nuclei of peripheral pig leucocytes, by ion exchange chromatography and by gel filtration on Sephadex G-100 and G-150. Only the inhibitor with the higher molecular weight was isolated in the homogenous form, in a single polypeptide chain with molecular weight of 68,000, designated Inhibitor-3. This inhibitor has an isoelectric point from 4.4 to 4.5 and is stable in buffer solutions from pH 3 to 8, and belongs to the type of so-called fast reacting inhibitors.
Mechanism of Accelerated Lysis of Blood Clots from Heparinised Blood
Authors: Morris C.J. , Williamson N. , Wolf P.
Published: April 2009

Heparin in a concentration of 0.2–0.5 units per millilitre of blood, plasma, or serum produced two opposite effects on fibrinolysis: (1) Fibrinolysis of whole blood clots showed moderate inhibition asjudged by the levels of fibrin degradation products (FDP) of sera separated after blood clotting with and without heparin. Heparin-induced inhibition of fibrinolysis was also seen when comparing the lysis rates of heparin-free clots in heparinised plasma and serum with the lysis rate of these clots in the heparin-free control samples. (2) Blood coagulation in the presence of heparin produced clots which lysed faster in buffer and buffer containing plasminogen and urokinase than control clots formed in blood coagulation of heparin-free blood. Clot weight measurement as well as FDP estimation of clot supernatant sera eliminated a reduced fibrin content of heparin clots as a possible cause for the observed accelerated clot lysis. Clot solubility measurements in 1 % monochlor acetic acid also ruled out defective factor XIII cross-linkage as a possible cause for the accelerated lysis rates of heparin clots. The clot structure of heparinised blood reflected the effects of delayed coagulation on the cell distribution throughout the clot; this produced gravitational separation of red blood cells from an overlying layer of leucocyte aggregates and fibrin. On the basis of the finding that the heparin batch used by us inhibited lysis and of previous reports on the effects of platelets and leucocytes on clot lysis, we concluded that accelerated lysis of clots from heparinised blood was not due to a specific action of heparin, rather it was brought about by delayed coagulation which induced a cell distribution in the clot favouring accelerated lysis.
Effects of the Gelatin Plasma Substitutes Haemaccel®, Plasmagel® and Plasmion® (Geloplasma®) on Collagen-, ADP- and Adrenaline-Induced Aggregation of Human Platelets in vitro
Authors: Stibbe J. , van der Plas P.M. , Ong G.L. , ten Hoor F. , Nauta J. , de Jong D.S. , Krenning-Douma E. , Gomes M.
Published: April 2009

The effect of some gelatin plasma substitutes (Haemaccel®, Plasmagel® and Plasmion® (Geloplasma®), which are widely used in Europe) on collagen-, ADP- and adrenaline-induced platelet aggregation in human PRP in vitro was studied under controlled conditions (pH, electrolyte composition). Haemaccel inhibited these aggregations, both in citrated as well as in heparinised PRP, whereas they were enhanced by both Plasmagel and Plasmion as compared to the appropriate control. Increasing the concentration of the inducer overcame the inhibition by Haemaccel. Haemaccel inhibited, while Plasmion enhanced 14C-serotonin release induced by collagen, ADP or adrenaline. Also in the presence of indomethacin (90 µM) Haemaccel inhibited aggregation induced by high concentrations of collagen and the primary aggregation induced by ADP and adrenaline, while Plasmion enhanced these aggregations. The inhibition by Haemaccel was not caused by binding of Ca2+ to Haemaccel.
Increased Release of Vascular Prostacyclin-Like Activity after Long-Term Treatment of Diabetic Rats with Bay g 6575
Authors: Chamone D.A.F. , van Damme B. , Carreras L.O. , Vermylen J.
Published: April 2009

10 male Wistar rats were made diabetic by an intravenous injection of streptozotocin. 10 sex and age-matched rats served as control animals. 5 of the diabetic and 5 of the control rats received Bay g 6575 (20 mg/kg orally) for 6 days each week throughout the whole study period (9–11 months). From these animals aorta was removed for prostacyclin bioassay based upon its platelet aggregation inhibitory effect. The diabetic rats treated with Bay g 6575 released significantly more prostacyclin than the controls (p < 0.005). Our study suggests further experiments in other animal models more susceptible to diabetic vascular lesions than the rat model to evaluate the possible beneficial role of the treatment with Bay g 6575.
The Influence of Various Combinations of Plasminogen and Streptokinase on Fibrinolysis
Authors: Gaffney Patrick J. , Joe Franklin , Rowe Edith A. , Whitaker A.N.
Published: April 2009

The lysis rates of 125I cross-linked plasma fibrin clots have been investigated following immersion in various buffered concentrations of streptokinase (SK), prior to (called the SK → plgn regimen) and after (called the plgn → SK regimen) enrichment with 2.0 U of plasminogen (plgn, lys-type). The SK → plgn regimen usually achieved total clot lysis with the most active lysis occurring following enrichment in 125–130 IU SK solutions, while only partial lysis was observed during the plgn → SK procedure. The effect of SK concentration was marked during the SK –plgn regimen while, during the plgn → SK treatment, its lytic rate effect never exceeded a factor of 2.0 over a wide concentration range of SK (8.0–20,000 IU/ml. The availability of plasminogen to perfuse the activator-rich clot seemed to be the prevailing influence on clot lysis and lysis of clots in plasma was inhibited by serum inhibitors, SK antibodies and plasma fibrinogen.
Inhibition of Activated Factors II, VII, IX, and X by Synthetic Organic Compounds Directed against the Active-Site Seryl Residue
Authors: v.d. Woerd-de Lange J.A. , van Dam-Mieras M.C.E. , Hemker H.C.
Published: April 2009

A series of 53 organic chemicals belonging to the groups of organic phosphates, sulfonyl derivatives and carbamates were screened for their activity against the coagulation factors IIa (thrombin), VIIa, IXa and Xa. Relatively specific inhibitors for the factors IIa, VIIa and Xa were found.
The Influence of Various Combinations of Plasminogen and Streptokinase on Fibrinolysis
Authors: Gaffney Patrick J. , Joe Franklin , Rose Edith A. , Whitaker Alan N.
Published: April 2009

The components found in l25I-labelled cross-linked plasma fibrin lysates obtained by alternate treatments with streptokinase (SK) and plasminogen (plgn) were examined by immunological and physicochemical methods. The more rapid and complete lysis achieved with the sequence SK → plgn was reflected by the near absence of the electropho-retically stable D dimer-E complex and high molecular weight soluble aggregates ( > 3 × 105 molecular weight), while these components were present in considerable amounts during the plgn → SK regimen. An assessment of the data from the rapid and slow regimens suggested that cross-linked high molecular weight complexes were initially released from fibrin, these being rapidly degraded to the D dimer-E complex which was subsequently converted to pure D dimer and E fragments. Two forms of the D dimer-E complex are proposed, probably varying in stability according to the number of attachment sites between the D dimer and E domains.
Platelet Aggregation and Thromboxane A2 Production after Adrenergic Stimulation in Young Healthy Humans
Authors: Neri Serneri Gian G. , Abbate Rosanna , Gensini Gian F. , Galanti Giorgio , Paoli Giovanni , Laureano Raffaele
Published: April 2009

The effects of adrenergic stimulation on platelet aggregation (platelet aggregation ratio; PAR), β-thromboglobulin (β -TG) release and plasma thromboxane B2 (T×B2) levels were investigated in 25 healthy young volunteers. Adrenergic stimulation induced by cold application was checked by evaluating the changes in the calculated vascular resistance in the forearm. A prompt increase in platelet aggregates and plasma β -TG and T×B2 concentrations was observed after adrenergic stimulation. PAR changed from resting values of 0.97 ± 0.05 to 0.75 ± 0.08 (p < 0.001) at the end of cold application. At the same time, β -TG plasma concentration increased from 32.09 ± 19.64 to 135.48 ± 37.97 ng/ml (p < 0.001) and T×B2 plasma levels changed from 0.49 ± 0.24 to 0.99 ± 0.39 pmol/ml (p < 0.001). TxB2 levels, but not PAR and β -TG concentration came back to the resting values at the end of the observation period (10 min). Aspirin, as the lysine acetylsalicylate equivalent to 5 mg/kg i.v. of acetylsalicylic acid, although able to completely inhibit platelet cyclooxygenase failed to inhibit the plasma T×B2 increase induced by adrenergic stimulation. This strongly suggests that the increase in plasma T×B2 following adrenergic stimulation is of extraplatelet origin. Also β-TG and PAR changes were not affected by aspirin administration.
Culture-Produced Subendothelium
Authors: Booyse F.M. , Quarfoot A.J. , Feder S.
Published: April 2009

Culture-produced subendothelium (SE) has been prepared from cultured porcine aortic endothelial cells (ECs) by a rapid freeze-thaw, ice-shearing method. En face preparations of this in situ SE material are essentially free of intact or damaged cells and cell debris and consist of an extensive meshwork of microfibrillar and amorphous material. Washed porcine platelets reacted extensively with this SE material and were associated with the SE as single adherent platelets, single spread platelets, and varying-sized platelet aggregates or ‘micro thrombi’. Platelet aggregates were asscociated only with the damaged or frayed edges of the SE, and the platelets had undergone extensive SE-induced contraction and degranulation, as indicated by transmission electron microscopy. Platelet-SE interaction was affected by pH, calcium, platelet concentration, rapid shaking and exposure time. Platelet-SE interaction was significantly enhanced by the addition of 0.1–1% citrated plasma or purified porcine F.VIIIR:WF. Pretreatment of the SE with thrombin, elastase, neuraminidase or hyaluroni-dase had no effect on platelet-SE interaction, whereas pretreatment with pepsin, plasmin, trypsin, α-chymotrypsin or collagenase decreased or completely abolished all platelet-SE interaction. Extraction of the SE with various solutions (high salt, detergents, etc.) had no effect on platelet-SE interaction, only solutions containing sodium dodecyl sulfate completely abolished all platelet-SE interaction.
Factor VII in Liver Cirrhosis
Authors: Orlando M. , Casalbore P. , Camagna A. , Lauro R. , Tardella L. , Hassan H.J.
Published: April 2009

Factor VII activity and factor VII cross-reacting material (CRM) in plasma of patients with liver cirrhosis have been studied before and after vitamin K1 parenteral administration. Subjects were divided into two groups according to the absence (group I) or the presence (group II) of the following clinical findings: ascites, portal hypertension, encephalop-athy. Factor VII activity and CRM show a statistically significant correlation (p < 0.001) in all patients. In group II, significantly reduced levels of both activity and CRM were found as compared to the reference and the group I values. No variations were found after vitamin K administration. Different thromboplastins, investigated with respect to their sensitivity for factor VII, acted differently. Patients with normal albumin levels also showed normal levels of factor VII activity and antigen. No correlation was found in group II. The data discussed suggest that in liver cirrhosis with unknown aetiology no immunologically detectable precursor of factor VII is present.
Factor IX Levels during Pregnancy in a Woman with Hemophilia B
Authors: Briet Ernest , Reisner Howard M. , Blatt Philip M.
Published: April 2009

The levels of factors VIII, II, and VII rise during pregnancy in normal women. In addition, increases in factor VIII levels have been observed in pregnant carriers of hemophilia A and in women affected with von Willebrand’s disease. The influence of pregnancy on factor IX levels is less clear. Consequently, we determined serial factor IX coagulant activities (IX:C) and factor IX antigen levels (IX:Ag) during the pregnancy of an affected carrier of hemophilia B who had baseline values of 13 % for both IX:C and IX:Ag levels. Neither level rose during pregnancy and the patient was treated with plasmapheresis and plasma infusions during the delivery and the postpartum period. Excessive bleeding did not occur.
Studies on Vitamin K-Dependent Factor Deficiency during Early Childhood with Special Reference to Prothrombin Activity and Antigen Level
Authors: Fujimura Yoshihiro , Mitnura Yoshiaki , Kinoshita Seiji , Yoshioka Akira , Kitawaki Tathuo , Yoshioka Keiichiro , Takamiya Osamu
Published: April 2009

8 young infants aged 14 days to 5 months with vitamin K-dependent factor deficiency were studied with special reference to prothrombin activity and antigen level. Among them, 3 infants had congenital bile duct atresia and 5 were breast-fed babies with severe hemorrhagic tendency of unknown cause. In the patients with both congenital bile duct atresia and breast feeding the ratio of prothrombin activity to prothrombin antigen was lower than 0.1. Furthermore, the arc of prothrombin antigen in these patients demonstrated a faster anodal shift than did normal prothrombin antigen on crossed immunoelectrophoresis. This abnormal prothrombin antigen was not consumed after recalcification of patient plasma, and adsorbed poorly on BaSO4. In addition, the abnormal prothrombin antigen disappeared from the patient plasma within a few days after parenteral administration of vitamin K. These results suggest that this abnormal prothrombin is PIVKA-II.
The Role of Platelet Surface Proteins Reacting with Heterologous Antibodies
Authors: Connellan J.M. , Barlow B. , Smith I. , Castaldi P.A.
Published: April 2009

Platelets were labelled with surface-labelling agents which identified up to six platelet membrane proteins. Three of these labelled proteins were recognised by a specific anti-platelet membrane serum by immunoprecipitation. Affinity fractionation of platelets with insolubilised IgG obtained from the anti-platelet membrane serum indicated a greater reaction between the antiserum and the platelet surface. Fab fragments from the antiserum inhibited ristocetin-induced aggregation of platelets and partially inhibited collagen-induced aggregation but did not affect ADP aggregation. Crossed immunoelectrophoresis of platelets using the anti-platelet membrane serum showed that the antiserum was specific for platelet membranes.
Platelet Sialic Acid in Malignant Disease
Authors: Martin J.F. , Kilbey R.S. , Paterson A.D.
Published: April 2009

n-Acetylneuraminic acid (NANA) was measured in the platelets and serum of normal subjects, patients with malignant disease, and patients with acute myocardial infarction. The malignant disease group had a mean platelet NANA 24% below normal and a serum NANA 68% above normal. Both results were highly significant. Samples from patients with acute myocardial infarction showed slightly reduced platelet NANA and slightly raised serum NANA, neither change being significant. There was no correlation between platelet and serum NANA in the neoplastic group.
Role of the Prostaglandin Biochemical Pathway in Platelet-Vessel Wall Interaction and Local Thrombosis
Authors: Bourgain R.H. , Andries R. , Six F.
Published: April 2009

Prostaglandins play an important role in the platelet-vessel wall interaction. The inhibition of PGI2 synthetase results in an increase of platelet thrombosis induced by adeno-sine diphosphate. Addition of exogenous arachidonic acid further increases the phenomenon. The ratio of cyclic endoperoxides (PGG2 and PGH2) to prostacyclin (PGI2) could well be the determining trigger in platelet-vessel wall interaction and local thrombosis.
Acetylsalicylic Acid in Combination with Dihydroergotamine for Preventing Thromboembolism
Authors: Zekert F. , Schemper M. , Neumann K.
Published: April 2009

In a prospective randomized clinical trial involving 150 patients who underwent major abdominal surgery, acetylsalicylic acid (ASA) and dihydroergotamine (DHE) were examined either alone or in combination for their potential to prevent thromboembolism. Combined treatment with ASA and DHE was found to be more effective in preventing the spread of thrombi and their propagation to the femoral veins.
Contractile Protein Studies on Platelets from Patients with Idiopathic Scoliosis
Authors: Muhlrad A. , Yarom R.
Published: April 2009

Measurements of total proteins, myosin, actin, actin-binding protein, and ATPase activity of myosin were examined in platelets from patients with idiopathic scoliosis and from healthy individuals. Abnormalities in the distribution of total and contractile proteins were revealed after frac-tionations. The insoluble fraction of the patients’ platelets had a higher, and the cytosol fraction had a lower than normal protein content. Similar differences were observed in the specific activity of myosin ATPase. These findings show that in patients with idiopathic scoliosis platelet defects exist and that their study might be useful in research of the disease.
Studies of Platelet Antibodies in Patients with Thrombocytopenic Purpura by Two Different Techniques
Authors: Wautier J.L. , Boizard B. , Patereau C. , Muller J.Y.
Published: April 2009

The direct antiglobulin consumption (DAC) test, used for the detection of platelet autoantibodies, was found to be positive in 86% of a group of 150 patients with thrombocytopenic purpura. The platelet radioactive Coombs’ (DRC) test was performed in 30 patients and the correlation between the two tests was statistically significant (r = 0.48, p < 0.01). The two tests were used in an indirect mode for the detection of antiplatelet antibodies in serum. The results of the two tests were in good agreement (r = 0.66, p < 0.001). There was not a statistically significant correlation between the level of platelet-associated IgG and the presence of platelet antibodies in the serum. These results indicate that the DAC test or DRC test can be used interchangeably for the detection of antibody in serum or of antibody bound to platelets, and that only the direct test, using the patients’ platelets, is useful in the diagnosis of autoimmune thrombocytopenic purpura.
Congenital Deficiency of α2-Plasmin Inhibitor in Three Sisters
Authors: Yoshioka A. , Kamitsuji H. , Takase T. , Iida Y. , Tsukada S. , Mikami S. , Fukui H.
Published: April 2009

3 young Japanese sisters with congenital α2-plasmin inhibitor (α2-PI) deficiency are reported. They have mild umbilical bleeding and/or repeated prolonged bleeding after minor trauma, but rarely spontaneous bleedings. The most characteristic hemostatic findings were shortened whole blood clot lysis time and euglobulin lysis time. Activities of all hemostatic factors except α2-PI were within normal range. Both functional and immunological absence of α2-PI were found in the plasma, and this failure to detect α2-PI was not corrected by the addition of the patient’s plasma of the first described case of α2-PI deficiency. Clinical and laboratory data revealed that these patients were probably homozygous for α2-PI deficiency and born of heterozygous parents, but not of consanguineous ones. Bleeding episodes due to deficiency of (α2-PI in these patients were well controlled by an antifibrinolytic agent, tranexamic acid.
Factor VII Padua 1
Authors: Croze M. , Brizard C.P.
Published: April 2009

A patient with a peculiar factor VII is described. The propositus is a 70-year-old man without any bleeding tendency. The coagulation pattern is characterized by a prolonged rabbit brain prothrombin time, a normal Stypven cephalin clotting time and a normal throm-botest. Factor VII activity is low when assayed using rabbit brain thromboplastin but is normal when assayed using ox brain thromboplastin. The neutralization test performed with an antifactor VII antiserum revealed a normal factor VII antigen level. A pedigree study has not been possible, the patient having no living relatives. No differences were observed between the biological results of our patient and those described by Girolami as factor VII + Padua.
Coagulation and Platelet Activation after Retinal Vein Occlusions
Authors: Mari Daniela , Santori Marisa , Bertoni G. , Mannucci P.M.
Published: April 2009

The role played by coagulation and platelet activation in the pathogenesis of retinal vein occlusions (RVO) has been evaluated by measuring beta-thromboglobulin (B-TG), circulating platelet aggregates (CPA), thromboxane B2 (T×B2) and fibrinopeptide A (FPA) in 25 patients less than 40 years old, investigated after the acute phase of RVO. FPA and B-TG were significantly higher than in healthy subjects; CPA and T×B2 were not different. These abnormalities, found in patients free from apparent generalized vascular disease, suggest that a thrombophilic state characterized by coagulation and platelet activation is present in a high proportion of young patients with RVO.
Function and Morphology of 111In-Labelled Platelets
Authors: Schmidt Kai Gjerløff , Rasmussen Jens Wæver , Lorentzen Martin
Published: April 2009

111In-labelled human platelets were aggregated with ADP and subjected to ultra-structural morphometric analysis. In addition, the hemostatic function in vivo and the ultra-structural morphology ex vivo of rabbit platelets were examined. The platelet isolation and labelling procedures exerted no certain influence on the aggregation response, and platelet surface/volume calculations did not indicate that platelet activation had taken place. Bleeding time experiments in rabbits indicated that the hemostatic effectiveness of the labelled platelets was unimpaired. Transfused 111In-labelled platelets isolated from the recipient rabbits exhibited fewer electronmicroscopic signs of platelet activation than the same platelets prior to transfusion. Our results indicate that the described procedure for isolation and 111In-labelling of platelets induces only insignificant damage to the platelets.
Effect of Collagen-Like Substances (Clq, Acetylcholinesterase and Elastin) on Collagen-Induced Platelet Aggregation
Authors: Csákó G. , Suba E.A. , Herp A.
Published: April 2009

The effects of collagen-like proteins on platelets were studied in human platelet-rich plasmas. The Clq subcomponent of complement (human), acetylcholinesterase (electric eel), and elastin (bovine) had no platelet aggregating activity, despite compositional homolo-gies with collagen in terms of hydroxyproline, hydroxylysine, proline and glycine contents. Upon preincubation with platelets, acetylcholinesterase was incapable of preventing the platelet aggregation triggered by collagen, whereas elastin exerted a weak and inconsistent blocking action. In turn, native Clq strongly inhibited collagen-induced platelet aggregation and ‘aggregated’ Clq, obtained by ultracentrifugation of freeze-thawed monomeric Clq, had a potentiating effect. These findings confirm the highly specific character of the platelet action of Clq.
Absence of Specific Binding of Receptor-Mediated Endocytosis, and of Secretion of Alpha-2-Macroglobulin by Cultured Endothelial Cells
Authors: Marynen P. , Van der Schueren B. , Van Leuven F. , Cassiman J.J. , Van den Berghe H.
Published: April 2009

The presence of an α2-macroglobulin (α2M) receptor, the receptor-mediated endocytosis of α2M-protease complexes, and the secretion of α2M by cultured endothelial cells derived from human umbilical vein and from bovine aorta were assessed with 125I-α2M trypsin. Only very low levels of endocytosis of 125I-α2M trypsin were measured, compared to the levels observed in normal human fibroblast cell layers. The absence of α2M receptors on endothelial cells, as measured in binding experiments at 4 °C, points to the nonconcentrative character of this process. The expression of an α2M receptor could not be induced by plating the cells at low densities or by growing them on collagen gels. The secretion of α2M by endothelial cells could not be detected. The production of α2M by human endothelial cells must, therefore, be lower than 3 ng/l06 cells/48 h, the lower limit of the assay.
Factor XIII Deficiency in Antibiotic-Associated Pseudomembranous Colitis and Its Treatment with Factor XIII Concentrate
Authors: Kuratsuji Tadatoshi , Oikawa Tadao , Fukumoto Tetsuo , Shimizu Shunichi , Iwasaki Yukio , Tomita Yukiharu , Meguro Takashi , Yamada Kaneo
Published: April 2009

The plasma factor XIII in a 5-year-old girl with antibiotic-associated pseudomembranous colitis decreased to 30%, although her bleeding time and other coagulation factors were normal. Factor XIII concentrate was able to control the severe hemorrhagic diarrhea and improve the laboratory data.
Use of Chromogenic Peptide Substrates in the Determination of Clotting Factors II, VII, IX and X in Normal Plasma and in Plasma of Patients Treated with Oral Anticoagulants
Authors: van Dieijen-Visser M.P. , van Wersch J. , Brombacher P.J. , Rosing J. , Hemker H.C. , van Dieijen G.
Published: April 2009

Spectrophotometric methods were used to assay the clotting factors II, VII, IX and X in plasma of 33 subjectively healthy human donors and in plasma of 98 patients receiving long-term oral anticoagulant therapy. In 33 normal subjects the interindividual variations in the plasma activities of the clotting factors II, VII, IX and X are respectively 12.2, 21.4, 11.0 and 15.0%. After correction for the assay variations the remaining biological variations are respectively 11.7, 21.2, 9.7 and 14.8%. Plasma from 98 patients receiving long-term anticoagulant therapy was assayed with ‘Thrombotest’, a clotting test in whole blood introduced by Owren and in these plasmas the activity of each of the vitamin K-dependent factors was assayed with spectrophotometric methods. For the clotting factors IX and VII, novel spectrophotometric methods were applied and the plasma activities thus measured were compared to results obtained with factor IX and VII clotting assays. Chromogenic activities of the different factors were correlated among each other and with 1/Thrombotest values. When the therapeutic range for Thrombotest values is set between 5 and 12.5% the corresponding therapeutic ranges for the activity of the factors II, VII, IX and X are respectively 12.6–36.1, 27.0–52.3, 23.1–49.3 and 18.9–36.2% (expressed as a percentage of the activity in normal pool plasma). The chromogenic assays for the factors II, VII, IX and X provide the same information on the therapeutic state of the patients in respectively 86.7, 78.6, 81.6 and 89.8% of the cases. Finally we discuss the suitability of the different assays to monitor oral anticoagulant therapy.
Metal Impregnation Abnormalities in Platelets of Patients with Idiopathic Scoliosis
Authors: Yarom R. , Meyer S. , More R. , Robin G.C.
Published: April 2009

A heavy metal impregnation technique revealed that platelets from patients with idiopathic scoliosis (IS) are more frequently ‘metallophilic’ and have a higher surface to volume ratio of the dense tubular system (DTS) than age-matched controls. These findings suggest that the fundamental defects in IS platelets involve membrane abnormalities related to cation binding and transport.
Increased Platelet Volume in Diabetic Retinopathy
Authors: Cagliero Enrico , Porta Massimo , Cousins Simon , Kohner Eva M.
Published: April 2009

Platelet volume was measured in 30 healthy controls and 87 diabetic patients, the latter subdivided according to the absence, presence and severity of retinopathy, to investigate if platelet size is related to microangiopathy. The platelet volume of the whole diabetic population was increased (p < 0.05) due to a higher percentage of large elements (p < 0.05). The patients with various degrees of retinopathy had similar increases (p < 0.05) in their platelet size, while those without complications occupied an intermediate position between normal controls and retinopathy patients. It is concluded that: (i) increased platelet size accompanies diabetic retinopathy, irrespective of its severity, and (ii) patients without this complication form a heterogeneous group, some of which already have alterations of platelet volume. The role of these abnormalities in the development and progression of diabetic microangiopathy remains to be established.
Inherited Deficiency of Antithrombin III in Two Italian Families
Authors: Manotti C. , Quintavalla R. , Megha A. , Ponari O. , Dettori A.G.
Published: April 2009

A significant decrease of plasma antithrombin III (AT III) levels, measured with four different biological and immunological methods, was found in 8 of 11 members of a Sicilian family (family DM) and in 3 of 14 members of a northern Italian family (family A). Different behaviour after oral anticoagulant treatment with acenocoumarin was seen in 2 long-term treated subjects. The propositus of family DM, who had had a long history of recurrent thrombosis, did not show any increase of AT III levels. A significant increase was, on the contrary, observed in the propositus of family A, who had suffered a recent thrombosis in a branch of the inferior mesenteric vein.
A Pharmacological Approach to the Inhibition of Platelet Adhesion and Platelet Aggregation
Authors: Verstraete M.
Published: April 2009

A first level of pharmacological interference with platelet function is located at the site of the agonist-receptor interaction (receptors for collagen, adenosine diphosphate, serotonin, fibrinogen). A second level of interaction is to prevent the mobilization of intra-cellular calcium ions which can be obtained by inhibition of phosphodiesterase, activation of cAMP (e.g. with prostacyclin analogues), inhibition of thromboxane A2 formation or blocking of its receptors. Compounds preventing the platelet contractile process or platelet secretion could theoretically also prevent some platelet functions.
Prostacyclin and 51Cr Release in Cultured Human Endothelial Cells
Authors: Brox Jan H. , Nordøy Arne
Published: April 2009

Conflicting reports have been published concerning the spontaneous release of prostacyclin (PGI2) from endothelial cells and vascular tissue in vitro. In this study the effect of using various incubation medias on the release of PGI2 and 6-keto-PGF1α from primary cultures of confluent endothelial cell monolayers (ECM), grown from human umbilical cord veins, was examined. The incubations were carried out for 5 min at 22 °C on a rocker platform. The release of these compounds differed substantially with the various incubation media. Hypotonic and thrombin-containing media produced the greatest release. The 51Cr release from prelabeled ECM was also assayed. A high correlation existed between PGI2, 6-keto-PGF1α and 51Cr occurring in the various media. Since 51Cr release is considered to be a marker of cell membrane damage, the study indicates that under in vitro conditions the amount of PGI2 released is related to the degree of cell injury.
Determination of Prothrombin by a Micro-Coagulation Method
Authors: Kirchhof B. , Schmale S. , van de Loo J.
Published: April 2009

In contrast to earlier assays, the prothrombin determination described here uses a two-step reaction: first, prothrombin is activated with human factor Xa, phospholipids, Ca++ and factor V; second, the amount of activated prothrombin is assayed by the proteolysis of added fibrinogen. The assay is dependent only on prothrombin, and independent of other components of thrombin generation. Carboxy- and decarboxyprothrombin can be differentiated by means of using Echis carinatus venom instead of factor Xa as activator. The micro-coagulation assay is compared with a conventional one-stage coagulation test, with a prothrombin determination using chromogenic substrate and immunologically by Laurell electrophoresis.
X-Ray Microprobe Analysis of Platelets
Authors: Yarom Rena
Published: April 2009

Platelets are well suited to X-ray microanalysis as there is no need for chemical fixation or sectioning, and the concentrations of calcium and phosphorus are above 10-3. The principles of the technique, the methods of specimen preparation, instrumental conditions during analysis and ways of quantitation are described. This is followed by a review of published reports and a brief summary of the author’s own work in the field.
Nonenzymatic Glycosylation of Collagen in Diabetes: Incidence on Increased Normal Platelet Aggregation
Authors: Le Pape A. , Guitton J.D. , Gutman N. , Legrand Y. , Fauvel F. , Muh J.P.
Published: April 2009

The effect of normal and nonenzymatically glycosylated rat type I acid-soluble collagen on normal human platelets was investigated. Glycosylated collagen was obtained either after in vitro incubation with glucose or from rats made diabetic by streptozotocin. The amount of nonenzymatically bound glucose was as follows: normal 2.3, diabetic 7.6 and in vitro glycosylated collagen 9.0 nmol/mg. When investigated under conditions leading to identical diameters and molecular packings for all the samples, the aggregation potency was markedly stronger for diabetic and glycosylated collagens than for normal ones. These results show the potential role of this posttranslational modification of collagen which can be considered as a risk factor in the thrombotic pathogeny of diabetes.
Platelet Malondialdehyde Production Kinetics after Cyclooxygenase Block
Authors: Nenci G.G. , Parise P. , Capodicasa E. , Berrettini M.
Published: April 2009

A modification of the original thiobarbituric acid (TBA) method for malondialdehyde (MDA) assay is described. The improvement is essentially based on the clearing effect of KClO4 that makes measurements more simple and sensitive. MDA values obtained in normal subjects were almost eightfold higher than those obtainable with Stuart’s original assay method, so that after cyclooxygenase block it was possible to assess platelet regeneration time even in thrombocytopenic patients with at least 60,000 platelets/µl and MDA production early after aspirin intake. To challenge this modification, platelet regeneration time was studied in normal subjects as well as in thrombocytopenic patients, either hypoplastic or idiopathic, and in hypoxemic patients with increased platelet consumption. The initial disappearance kinetics of platelet MDA and thromboxane B2 production after aspirin suggests that TBA-reactive material is synthesized through the lipoxygenase pathway. The reversible block determined by acetylsalicylic acid and salicylate on hydroperoxieicosatetraenoic acid peroxidase can be responsible for the initial increase of this TBA-reactive material.
The Politics of Tripartite Cooperation in New Democracies: A Multi-level Analysis
Authors: Aleman Jose
Published: April 2009

The literature on labor politics explains cooperation among unions, employers and state representatives in new democracies as a function of alliances between politically influential unions and left governments. This article introduces an original dataset of labor agreements in new democracies (1994—2004). Using Boolean analysis, it shows that while left governments are typically associated with more labor market regulation, they are not sufficient for social pacts to emerge in new democracies. Instead, protective labor market institutions and practices explain most instances of cooperation. Further analysis reveals this to be the case for all types of pacts analyzed.
Dangerous (Internal) Foreigners and Nation-Building: The Case of Canada
Authors: Dhamoon Rita , Abu-Laban Yasmeen
Published: April 2009

In this article we develop a theoretical framework attuned to the relationship between discourses of security, race/racialization, and foreignness. Applying this framework to three historic instances of Canadian national insecurity (Japanese-Canadian internment, the Front de libération du Québec crisis, and the Kanehsatake/Oka crisis), we argue that “foreignness” is produced and regulated in historically specific ways with consequences for how “the nation” is viewed. We demonstrate how this is especially evident in relation to racialized constructions of “internal dangerous foreigners.” Our framework and findings invite larger disciplinary consideration of the post-September 11 security environment both in and outside Canada.
Effects of Chronic Exposure to Crack Cocaine on the Respiratory Tract of Mice
Authors: Herculiani Percyleine P. , Pires-Neto Ruy C. , Bueno Heloisa M. S. , Zorzetto Júlio C. , Silva Luiz C. , Santos Ángela B. G. , Garcia Raphael C. T. , Yonamine Mauricio , Detregiachi Cláudia R. P. , Saldiva Paulo H. N. , Mauad Thais
Published: April 2009

Smoked cocaine (crack cocaine) causes several forms of injury to the respiratory tract, including asthma exacerbations, lung edema and hemorrhage, and nasal mucosal alterations. Few studies, however, have assessed respiratory tract pathology in habitual users of crack cocaine. Here, we describe the histological alterations in the respiratory tract of mice caused by chronic inhalation of crack cocaine. Twenty 2-month-old BALB/c mice were exposed to the smoke of 5 g crack cocaine in an inhalation chamber once a day for two months and compared to controls (n = 10). We then morphometrically analyzed nose and bronchiolar epithelial alterations, bronchiolar and alveolar macrophage cell density, alveolar hemosiderin content, and in addition determined the vasoconstriction index and the wall thickness of pulmonary arteries. The serum cocaine level was 212.5 ng/mL after a single inhalation. The mucus content of the nasal epithelium increased in crack-exposed animals, and the nasal and bronchial epithelium thickness decreased significantly. The alveolar hemosiderin content and the alveolar and bronchiolar macrophage cell density increased in animals exposed to crack. The vasoconstriction index increased in the pulmonary arteries of the exposed group. Chronic crack cocaine inhalation causes extensive histological changes along the entire respiratory tract.