bluuebunny/crossref_metadata_2025 huggingface dataset:
Exercise Induces in vivo Platelet Activation in Patients with Coronary Artery Disease and in Healthy Individuals
Authors: Schernthaner G. , Mühlhauser I. , Böhm H. , Seebacher C. , Laimer H.
Published: April 2009

Recently, conflicting results have been published about a possible relationship between platelet activity and exercise-induced myocardial ischemia. The present study was performed to investigate platelet behavior during a graded symptom-limited bicycle ergometer test both in relation to the intensity of exercise and to exercise-induced myocardial ischemia. Plasma concentrations of platelet factor 4 (PF4) and β-thromboglobulin (β-TG) were measured by radioimmunoassays in 53 patients who had had acute myocardial infarction 10 weeks before the study and, for comparison, in 9 healthy individuals. In the whole group of the 53 patients there was no significant alteration in platelet-specific proteins during exercise, whereas physical activity induced a 2- to 3-fold increase in β-TG and PF4 levels in the controls. However, on differentiation of the patients as to their individual exercise performance, significant exercise-associated platelet activation was demonstrable in those who reached more than 75% of their calculated maximal working capacity, whereas no correlation was found between platelet activity and exercise-induced myocardial ischemia. Thus, the results from this study indicate that in vivo platelet activation is a physiological phenomenon which occurs when a certain degree of physical intensity is exceeded, independent of the precipitation of myocardial ischemia.
Localization and Immunological Characterization of Plasminogen Activators in Human Prostate Tissue
Authors: Kirchheimer J. , Binder B.R.
Published: April 2009

In tissue sections of human hyperplastic as well as carcinomatous prostate glands ñbrinolytic activity could be attributed to collecting ducts and vessel walls. Inhibition studies with antibodies directed against human urokinase (u-PA) or tissue plasminogen activator (t-PA) revealed the presence of a plasminogen activator completely inhibitable by anti-t-PA IgG in the vessel walls, while in collecting ducts the plasminogen activator activity was inhibited by anti-u-PA IgG to only 80% and by anti-t-PA IgG to about 20%. A mixture of anti-u-PA and anti-t-PA IgG was able to inhibit fibrinolytic activity in collecting ducts completely. In carcinomatous prostate glands total fibrinolytic activity was significantly higher, but localization and relative contribution of anti-u-PA-inhibitable and anti-t-PA-inhibitable plasminogen activators remained the same.
Molar Antithrombin Concentration in Normal Human Plasma
Authors: Conard J. , Brosstad F. , Lie Larsen M. , Samama M. , Abildgaard U.
Published: April 2009

Crude, commercial thrombin preparations and purified bovine thrombin were incubated with normal human reference plasma and the amount of thrombin inactivated was calculated. 1 ml of human plasma inactivated 140–193 NIH U of the various crude thrombin preparations. In the presence of heparin, a lower thrombin-inactivating capacity of plasma was confirmed using crude thrombin, but this phenomenon was less pronounced with the purified thrombin preparation. The molar concentration of the purified bovine thrombin was determined by active site titration. Comparing with protein concentration (A280) > this preparation was 92% pure. 1 ml of human plasma inactivated 2.57 µmol of thrombin in the absence of heparin, and 2.50 µmol with heparin. Assuming 1:1 stoichiometry in the thrombin-antithrombin reaction, these results suggest that the concentration of antithrombin in the pooled reference plasma is approximately 2.57 µmol/l or 0.15 g/l.
Contribution of the Haematocrit to the Bleeding Time
Authors: Small M. , Lowe G.D.O. , Cameron E. , Forbes C.D.
Published: April 2009

Bleeding time, platelet count and haematocrit were performed in 64 normal, anaemic and polycythaemic subjects with normal renal function and platelet counts over 100 B× 109/l. There was a significant inverse correlation between the bleeding time and haematocrit (r = -0.47) and an inverse correlation of the haematocrit and platelet count (r = -0.46). We suggest that the effect of the haematocrit on the bleeding time could explain the shorter bleeding time in men compared to women, and the shorter bleeding time in subjects with arterial disease, in whom an increased haematocrit is commonly found.
Fibrinolytic Activity after Administration of Diflunisal and Aspirin
Authors: Green David , Davies Richard O. , Holmes Geoffrey I. , Johnson Cynthia , Kohl Helga , Reynolds Nancy , Ts’ao Chung-hsin
Published: April 2009

A double-blind, randomized, placebo-controlled clinical trial was conducted to determine whether fibrinolysis was increased by the chronic administration of aspirin or diflunisal. Healthy male and female volunteers were randomized to receive either aspirin (1,300 mg every 12 h; 10 subjects), diflunisal (1,000 mg initially, then 500 mg every 12 h; 10 subjects), or placebo (10 subjects) for 8 days. Fibrinolytic activity was examined with the clot lysis assay, using native whole blood, platelet-rich plasma, and platelet-poor plasma, and with the kaolin-activated euglobulin lysis test. In addition, measurements were made of fibrinogen, fibrin/fibrinogen degradation products, plasminogen, and the thrombin time. Clot lysis was greater in whole blood and platelet-rich plasma than in platelet-poor plasma, and increased lysis was observed in specimens obtained in the afternoon as compared to those obtained in the morning. Fibrinolytic activity in the afternoon samples was significantly enhanced by both aspirin and diflunisal at the start of the trial (p < 0.05), but by the afternoon of day 8, only aspirin showed some enhancement. Fibrinolytic activity, as measured by the euglobulin lysis time, actually declined in all study groups during the course of drug administration. No significant changes were recorded in any of the other assayed hemostatic parameters. We conclude that aspirin and diflunisal exert a modest, nonsustained enhancing effect on fibrinolysis in normal subjects.
Waist Circumference Values of Nigerian Children and Adolescents
Authors: Senbanjo I.O. , Njokanma O.F. , Oshikoya K.A.
Published: April 2009

Aims: This study aimed to determine the waist circumference (WC) of apparently healthy Nigerian children and adolescents and to compare the obtained values with available data for children from other parts of the world. Methods: A representative sample of children from 7 schools in Abeokuta, a state capital in South West Nigeria, was selected using the multi-staged random sampling technique. The sample population consisted of 570 children with ages ranging from 5 to 19 years. Results: WC increased with age in both sexes. The mean value of WC of children aged 5–9 years was about the same in both sexes (p = 0.113). However, in children older than 9 years, females had higher WCs than males (p = 0.000). Comparison of the 50th percentile WC of Nigerian children with that of American and Spanish children showed that both Nigerian male and female children had the lowest WC values. However, the values were similar to British male children up to 9 years and female children up to 14 years. Conclusion: The WC value varied with age, sex and race. These data are expected to serve as a baseline against which future data can be compared.
CD4+ T Cells and Immunosenescence – A Mini-Review
Authors: Maue Alexander C. , Haynes Laura
Published: April 2009

Age-related declines in immune function are associated with reduced humoral responses following vaccination or infection. Central to this defect is a decline in naïve CD4+ T cell function. In this review, we discuss factors intrinsic and extrinsic to the CD4+ T cell compartment that affect host immunity and propose means by which deficient CD4+ T cell function can be fully restored in the aged.
Changes in Histomorphometric and Mechanical Properties of Femurs Induced by Acupuncture at the Shenshu Point in the SAMP6 Mouse Model of Senile Osteoporosis
Authors: Zhang Xuezhu , Peng Yingmei , Yu Jianchun , Liu Cunzhi , Cheng Haiyan , Liu Lu , Han Jingxian
Published: April 2009

Background/Objective: The effect of acupuncture on the changes in the histomorphometric and mechanical properties of femurs in senescence-accelerated mice strain P6 (SAMP6) was evaluated in this work. Methods: Six-month-old male SAMP6 and SAMR1 mice were allocated to 1 of 4 groups: SAMP6 control group (Pc), SAMP6 non-acupoint control group (Pn), SAMP6 acupuncture group (Pa) and SAMR1 control group (Rc). The Pa group was acupunctured at the Shenshu point (BL23) once daily for 8 weeks. Two non-acupoints at the hypochondria were needled for the Pn group. Mice in the other 2 groups were grasped using the same method as for the Pa group. The serum testosterone and osteocalcin (OC) levels were determined by radioimmunoassay. The histomorphometric data were obtained from undecalcified specimens, and the mechanical properties of the femur were assessed by the 3-point bending test. Results: After acupuncture treatment, the decreased serum testosterone level in SAMP6 mice increased markedly, whereas the increased OC concentration declined sharply. The bone histomorphometric and mechanical indexes of SAMP6 mice also improved significantly. The values of trabecular thickness, trabecular bone volume, osteoid volume, mineral apposition rate and bone formation rate in Pa mice increased by 20.4, 18.1, 14.1, 9.9 and 14.7%, respectively, compared with Pc mice. The scores for ultimate force, yield force, elastic stress, ultimate stress and energy to yield force for Pa mice were significantly higher than those of Pc and Pn mice. Conclusion: Therefore, acupuncture at BL23 was effective in promoting bone formation, restoring the amount of bone volume, improving bone architecture and reversing osteoporosis in SAMP6 mice to some degree by enhancing the secretion of testosterone and declining bone turnover.
Inhibition of the Thrombin-Platelet Reaction by Hirudin
Authors: Hoffmann A. , Markwardt F.
Published: April 2009

The influence of hirudin on the thrombin-platelet reaction was studied by determination of thrombin-induced serotonin release from blood platelets. The dissociation constant for the thrombin-hirudin complex calculated from data obtained by measuring the platelet reaction (Ki 50 pmol/l) was in accordance with the value obtained by determination of fibrinogen clotting. Prevention of the effect of thrombin on platelets required the addition of hirudin in at least 10-fold molar excess. The release of serotonin could be immediately stopped by hirudin at any time when the special conditions for the reaction of thrombin with the tight-binding inhibitor and the receptors on the platelet surface were taken into account.
Gelation of Fibrinogen in Plasma
Authors: Regañon E. , Vila V. , Aznar J.
Published: April 2009

Studies of the turbidity profiles of diluted (1/55, v/v) normal plasma, thrombin activity free serum plus commercial fibrinogen, and 0.15 M NaCl, pH 7.4, plus commercial fibrinogen, activated by thrombin or reptilase and measured at 350 nm, have shown that the latency time (LT) hardly varies for the fibrinogen concentration within limits of 0.03–0.15 mg/ml; however, it does vary for the thrombin concentration. The rate of gelation (RG) varies linearly with the fibrinogen (FG) concentration, conforming to the equation RG = 0.027 (FG)1.8; it hardly varies for thrombin concentrations greater than 0.50 NIH U/ml. On the other hand, RG values obtained for 0.46 NIH U/ml of thrombin or 0.92 BU/ml of reptilase show no significant differences. The variation in LT for the thrombin or reptilase concentration allows the rate of activation to be estimated, giving values of 5.9 × 10-12 and 3.2 × 10-12mol/U/s, respectively, for a fibrinogen concentration in plasma of 1.1 × 10-10 mol/ml. The mean value estimated for the ratio LT/FG in normal plasma is 35.76 ± 18.3 and 85.62 ± 18.3s mg-1 ml for activation by thrombin and reptilase, respectively. We have studied in normal plasma the parameters that define the gelation of fibrin as measured by turbidity curves and their variation according to the fibrinogen concentration. This permits us to establish the kinetics of fibrin gel formation and normal range values.
Automated Determination of Heparin with Chromogenic Substrates
Authors: van Putten Janjaap , van de Ruit Marjo , Beunis Marlène , Hemker Coenraad
Published: April 2009

Spectrophotometric heparin assays which are based on the catalytic effect of heparin on either the inactivation of thrombin or that of factor Xa by antithrombin III, were adapted for use in a laboratory batch analyzer. Optimal conditions were determined for assays using the chromogenic substrates Chromozym-Th and S-2238 with thrombin, and S-2222 with factor Xa. Inactivation of the clotting enzyme by antithrombin III was stopped by addition of chromogenic substrate. Assays thus obtained appeared to be applicable in a wider range of heparin concentrations and were less dependent on plasma antithrombin III concentration that known manual spectrophotometric methods. The best results were obtained with the methods based on thrombin inactivation and applying a logarithmic reference curve.
Automated Spectrophotometric Heparin Assays
Authors: van Putten Janjaap , van de Ruit Marjo , Beunis Marlène , Hemker Coenraad
Published: April 2009

Three automated spectrophotometric heparin assays were investigated. The day-to-day reproducibilities in routine laboratory use were compared with two commercial manual kits for heparin determination. Regression analysis of the activated partial thromboplastin time (APTT) on results of any of the heparin assays shows that the heparin concentration cannot be deduced from the APTT values found in patients receiving heparin. The automated heparin assays that employ thrombin and Chromozym-Th or S-2238 were found to be most suitable for routine heparin determination. Heparin concentrations obtained from assays based on factor Xa inactivation were not significantly different from those employing thrombin (p < 0.01), but revealed a wider standard deviation. The relationship between APTT and heparin level found was not related to the plasma antithrombin III concentration. The extra antithrombin III that is added in the assays had to be freed of heparin neutralising activity to obtain reliable estimates of the heparin concentration in the low range (0–200 U/l).
Determination of Low Molecular Weight Heparin in Clinical Laboratory
Authors: van Putten Janjaap , van de Ruit Marjo , Beunis Marlène , Hemker Coenraad
Published: April 2009

The applicability was investigated of automated spectrophotometric heparin assays and three clotting assays for determination of two low molecular weight (LMW) heparin fractions: Org 10172 and DxN10 and two infractionated commercially available heparins. The relative activity of the two commercially available heparins was similar in the anti-Xa assay, in the anti-IIa assay and in 3 clotting assays. The LMW heparins showed markedly different relative activity in all 5 assays. The activities of those heparin preparations relative to the standard heparin were compared in the 5 assays, but standardization against a standard heparin preparation appeared impossible. Methods of heparin determination can be used to monitor treatment with a heparin preparation only if the same preparation is used as a reference substance.
Studies on Precursor Proteins PIVKA-II, -IX, and -X in the Plasma of Patients with Ηemorrhagic Disease of the Newborn’
Authors: Fujimura Y. , Okubo Y. , Sakai T. , Sugimoto M. , Takase T. , Yoshioka A. , Fukui H.
Published: April 2009

Factors II, IX, and X in the plasmas of 10 patients with ‘hemorrhagic disease of the newborn’ were investigated by means of electroimmunoassay and crossed immunoelectrophoresis (CIE). The biological activity was within 4.2–30 U/dl for factor II, 5.1–20 U/dl for factor IX, and 5.2–24 U/dl for factor X, whereas the immunological antigen was within 33–58, 25–50, and 35–60 U/dl, respectively. Thus, for all factors, 1.7 times more antigen than activity was present. The CIE pattern of factors II and IX in the presence of Ca++ ions clearly showed a biphasic precipitin arc, and in the absence of Ca++ ions, only one precipitin arc was observed. These results implied the presence of precursor proteins PIVKA-II and -IX in the plasma. However, even in the presence of Ca++ ions the CIE pattern of factor X antigen in the patient plasmas only showed a single precipitin arc with a slightly faster than normal electrophoretic mobility. PIVKA-II, -IX, and the abnormal factor X antigen (PIVKA-X) disappeared within 24 h after the patients were treated with vitamin K.
Prekallikrein Behaviour in Chronic Active Hepatitis and in Cirrhotic Patients
Authors: Cordova C. , Musca A. , Violi F. , Alessandri C. , Ferro D. , Piromalli A. , Balsano F.
Published: April 2009

Prekallikrein (Prekk), antithrombin III (ATIII), plasminogen and alpha2-anti-plasmin were evaluated in chronic active hepatitis and in liver cirrhotic patients and correlated with Normotest. Prekk, ATIII and plasminogen were significantly decreased in chronic active hepatitis as well as in liver cirrhosis. Alpha2-antiplasmin levels in chronic active hepatitis patients did not differ from controls; liver cirrhotic patients, on the contrary, showed significantly low values of alpha2-antiplasmin. Prekk, ATIII and plasminogen were significantly correlated with Normotest in both groups, but when cirrhotic patients were divided into the compensated and decompensated state only Prekk was correlated with Normotest in the decompensated state. The investigation seems to suggest that Prekk could be a reliable index for protein liver failure.
Hereditary Factor VII Deficiency: Report of a Case of Intracranial Hemorrhage
Authors: Hassan H.J. , Casalbore P. , De Laurenzi A. , Petti N. , Sinibaldi° L. , Orlando M.
Published: April 2009

A case of factor VII deficiency in a 52-year-old woman who developed central nervous system hemorrhage is here reported. Screening coagulation tests were all normal except for prothrombin time, normotest and thrombotest. Specific assays of vitamin Independent factors revealed that factor VII activity was reduced (11 U/dl). The studies of the family demonstrated that 2 sisters out of 4 were heterozygous for the defect. The activity of factor VII in the offspring, classified as obligatory carriers, ranged between 62 and 78 U/dl, the antigen between 55 and 75 U/dl. The wide variability of factor VII in normal people and the possible compensative effect of normal alleles in carriers do not allow to define the variant, namely if the patient is a CRMR homozygote or a CRMR/CRM- double heterozygote.
Acquired Factor VIII Inhibitor in a Non-Haemophilic Patient: Successful Treatment with Plasma Exchange Associated with Factor VIII Concentrate and Immunosuppressors
Authors: Paracchini M.L. , Rocchini G.M. , Renoldi P. , Fiorina G.F. , Gosso P. , Onida L. , Geniram A. , Marini U. , Gibelli A.
Published: April 2009

We report the successful treatment of a 5 5-year-old man with an acquired factor VIII inhibitor, the appearance of which followed surgery for a carcinoma of the biliary tract. The patient, who had recurrent life-threatening bleeding episodes, was treated with intensive plasmapheresis, factor VIII concentrates, azathioprine and methylprednisolone. Disappearance of the inhibitor was observed after the second series of plasma exchanges. Controls 2 and 3 months after treatment confirmed the complete absence of the inhibitor and normal levels of factor VIII. The crucial role of plasma exchange is considered and discussed.
Heparin Neutralization during Collection and Processing of Blood Inhibited by Pyridoxal 5′-Phosphate
Authors: van Putten Janjaap , van de Ruit Marjo , Beunis Marlène , Hemker Coenraad
Published: April 2009

Spectrophotometric heparin assays are expected to be independent on clotting factors, either activated or nonactivated, but could be sensitive to heparin neutralization during blood collection. Is was shown that more than 200 U of heparin/1 plasma can completely be neutralized during blood processing. Because the heparin neutralization is not constant but dependent on the sample as well as on the type of sample handling, one cannot beforehand compensate and correct the results for possible heparin neutralization. We tested the use of pyridoxal 5’-phosphate (PLP) to prevent heparin neutralization. As the use of PLP in the citrate tube decreased the heparin neutralization to a negligible effect, PLP-citrate tubes are to be preferred for all plasma heparin determinations.
Blood Coagulation and Platelet Function following Maximal Exercise: Effects of Beta-Adrenoceptor Blockade
Authors: Small M. , Tweddel A.C. , Rankin A.C. , Lowe G.D.O. , Prentice C.R.M. , Forbes C.D.
Published: April 2009

Alterations of platelet function and blood coagulation may occur with exercise or β-adrenoceptor blockade. To determine if β-blockade could modify exercise-induced changes in haemostatic factors we performed a double-blind study of actue strenuous exercise in normal males with and without β-blockade. Exercise increased prostacyclin and plasminogen activator levels but there was no evidence of thrombin generation as indicated by unchanged platelet aggregation responses, β-thromboglobulin and íibrinopeptide A levels. The only alteration in coagulation by β-blockade was a reduction in the factor VIII:C and VIII:RAg rise after exercise and this modification may be relevant to the protective effect of these drugs in patients with coronary artery disease.
Studies on the Binding of Complement Factor C3 to the Surface of Human Blood Platelets
Authors: Endresen Gerhard K.M. , Mellbye Ove J.
Published: April 2009

Employing immunofluorescent staining methods, platelets from several adult patients with chronic idiopathic thrombocytopenic purpura, with systemic lupus erythematosus, and with classical rheumatoid arthritis stained positively with antisera to C3(β1C and C3dg(α2D). In some cases, platelet-bound C3dg antigens, but no evidence of other C3 antigens were observed. Platelets that were positive for C3 and/or C3dg were always positive for IgG or for both IgG and IgM. Platelets from normal subjects stained negatively for C3, C3dg, IgG, and IgM. Furthermore, various incubation experiments were performed to investigate the uptake of C3 and its subfragments on normal platelets. Positive platelet staining for C3 was obtained after incubation with normal and C3b-containing sera, but not after incubation with native C3. Platelets incubated with C3c(β1A)/C3dg-containing serum gave a positive staining for C3dg, but not for C3c. None of the sera stained positively for IgG or IgM. Thus, in contrast to platelets from several of the patients, no in vivo binding of C3 antigens on normal platelets could be established. However, in vitro they could take up both C3b and C3dg, apparently by specific binding to platelet surface structures.
Platelet Aggregation in Arterioles of the Hamster Cheek Pouch and in Heart Transplants: Its Tissue-Dependent Influencibility by Acetylsalicylic Acid and Nafazatrom
Authors: Herrmann K.S. , Seuter F.
Published: April 2009

Different, tissue-dependent antiaggregatory properties of endothelial cells are suggested by in vitro findings, which show different spectra and amounts of arachidonic acid products to be synthesized by vessels of different type and origin. Platelet aggregation was assessed in vivo in native arterioles of the hamster cheek pouch and in arterioles of heart transplants by intravascular excitation of fluorescein isothiocyanatedextran (FITC-d). The time to aggregate appearance (TAA) was determined, i.e. the interval from onset of FITC-d excitation until the first aggregate was seen to adhere to the vessel wall. Two groups were pretreated with 100 μg/kg nafazatrom and 100 mg/kg acetylsalicylic acid (ASA), both potent antithrombotic drugs. Nafazatrom has been shown to stimulate prostacyclin release from endothelial cells, whereas ASA blocks cyclooxygenase both in platelets and vessel walls. TAA was the same for native arterioles of both types. Nafazatrom was equally effective in both vessels, and about three orders of magnitude more potent than ASA in prolonging TAA. ASA was twice as effective in arterioles of the heart as it was in those of the skin type, indicating that tissue-dependent mechanisms achieve the antiaggregatory potency of the vessel walls. It is concluded that further in vivo studies on platelet aggregation and thrombus formation should be performed on cardiac vessels directly and not on vessels of different origin. The presented model may be a useful tool for investigating the mentioned tissue-dependent mechanisms of thrombus formation in vivo.
Isolation of Small Molecular Forms of Factor VIII/von Willebrand Factor from Plasma
Authors: Perret B.A. , Furlan M. , Beck E.A.
Published: April 2009

Cryoprecipitated factor VIII/von Willebrand factor (FVIII/vWF), freed of fibrinogen by clotting with calcium and Defibrase®, was chromatographed on Sepharose CL-2B. Fractions containing lower-molecular-weight forms of FVIII/vWF comprised coprecipitated plasma proteins of similar molecular weights. The major contaminants, fibronectin and IgM, were removed by affinity chromatography on gelatin- and anti-IgM-agarose, respectively. Finally, pure low-molecular-weight FVIII/vWF protein was harvested in the void volume fraction of a Sepharose CL-6B column. The smallest multimers had the size of the tetramer of the basic subunit chain of FVIII/vWF.
CRM+ Severe Fletcher Factor Deficiency Associated with Graves’ Disease
Authors: Kyrle P.A. , Niessner H. , Deutsch E. , Lechner K. , Korninger C. , Mannhalter C.
Published: April 2009

A 59-year-old male patient with Graves’ disease and severe hereditary Fletcher factor deficiency is described. PKK clotting activity as well as the activity by a chromogenic substrate method (Chromozym PK®) was less then 0.01 U/ml. In contrast to functional tests, the immunological assay (Laurell method) showed a PKK antigen concentration of 0.25 U/ml, indicating the presence of an abnormal nonfunctional PKK molecule (CRM+ variant). An inhibitor was excluded since the patient plasma did not inactivate partially purified PKK. Investigation of 11 family members revealed a reduction of the PKK clotting activity in 9 relatives of the patient. Since Graves’ disease is considered an autoimmune disease, our case represents an example of an association of a severe hereditary deficiency of a contact factor and an autoimmune disease.
Evaluation of an Automated Prothrombin Assay Using a Chromogenic Substrate
Authors: Conkie J.A. , McCall Frances , Walker Isobel D. , Davidson J.F.
Published: April 2009

The performance of a commercially available assay for the determination of prothrombin by a chromogenic substrate method has been evaluated for use on an automated clinical analyser. The method was rapid and simple; accuracy, precision and sensitivity were satisfactory, while carry-over was negligible. Determinations were performed on 170 plasma samples from patients on long-term oral anticoagulant therapy, using the automated amidolytic method; comparison of the prothrombin levels with results obtained by the prothrombin time and Thrombotest methods provided highly significant correlations.
Maintenance of Platelet Viability after Platelet-Labeling with Fluorescein Isothiocyanate
Authors: Klaverkamp J. , Völkl K.-P.
Published: April 2009

Possible effects of an ex vivo fluorescent labeling procedure of blood platelets on the platelet viability were examined by different function tests. The degree of the impairment of the platelet function proved to be principally correlated with the dye concentration used during the labeling procedure. However, the physiological properties of the labeled platelets obviously remain unrestricted by using intraplatelet fluorescein isothiocyanate (FITC) concentrations below 0.55 mg/1011 platelets, corresponding to 8.5 × 106 FITC molecules bound to one platelet. A procedure for fluorescent labeling of blood platelets is described which is considered to be preferably suitable to prepare platelets for vital microscopic platelet observations.
Investigations on Platelet Function in Diabetes mellitus
Authors: Kubisz P. , Arabi A. , Holan J. , Cronberg S.
Published: April 2009

Investigations on the platelet function in diabetes mellitus were performed on 28 patients with insulin-dependent diabetes and in 33 healthy controls of similar age. In the diabetic patients it was possible to induce 50% of maximal aggregation by lower concentrations of adenosine diphosphate or arachidonic acid than in the controls. In the presence of N-ethyl maleimide, platelets from diabetic patients produced significantly more malondialdehyde than those from normal controls. After addition of arachidonic acid the platelets from the diabetic patients also synthesized more thromboxane B2. This synthesis of thromboxane was inversely correlated to the minimal concentration of arachidonic acid necessary to induce 50% platelet aggregation. Circulating platelet aggregates were more common in the diabetic patients than in the controls. Plasma levels of β-thromboglobulin and platelet factor 4 were raised in parallel in the diabetic patients and correlated with the increased production of thromboxane B2 by the platelets from the same patients. Platelets from patients with diabetes thus demonstrated signs of hyperreactivity both in vivo and in vitro. This may be of clinical importance for the development of vascular complications in this disease.
Molecular Exchange between Blood and in vitro Thrombi
Authors: Iga Yoshiro , Stella Sylvia R. , Chandler Bleakley
Published: April 2009

Uptake of radioiodinated Lys-plasminogen (125I-PLG), albumin (125I-ALB), and tritiated water (3H-H2O) by in vitro thrombi and interchange of these molecules with blood in an in vitro perfusion system were investigated. The radioisotopes were taken up by thrombi either by incorporation during formation in radiolabelled blood or by perfusion of preformed nonradioactive thrombi in radiolabelled blood. Release of the radioisotopes into a perfusion medium of nonradiolabelled blood was then monitored over a 120-min period. The small molecules of 3H-H2O were rapidly released from the thrombi and achieved equilibrium with the perfusion medium by 120 min in that the specific radioactivity (cpm/mg) of the thrombi equalled that of the medium. The larger molecules of 125I-PLG and 125I-ALB were more slowly released and did not reach equilibrium with the perfusion medium over the period studied. Release of 125I-ALB was intermediate between that of 3H-H2O and 125I-PLG. The greater retention of 125I-PLG by the thrombi was consistent with the high binding affinity of plasminogen for fibrin. The demonstrated movement of these radioisotopes between medium and thrombus suggests that thrombi exist in blood in a dynamic state of flux, exhibiting a fluid exchange of molecules between the interstitial compartment of the thrombus and blood.
The Role of Complement in the Induction of Thromboplastin Synthesis
Authors: Østerud Bjarne , Olsen Jan Ole , Benjaminsen Anne Welle
Published: April 2009

Complement appears to be an important system for cell activation in circulating blood. It is established that granulocytes may be stimulated through complement activation. In the present paper we propose also a central role of complement in the induction of thromboplastin synthesis in blood monocytes and endothelial cells.
Cancer Cell Procoagulants and Their Pharmacological Modulation
Authors: Donati Maria Benedetta , Semeraro Nicola
Published: April 2009

Cancer cells may promote fibrin formation in the tumor microenvironment through availability of procoagulant activities which are mainly of two types: tissue thrombo-plastin-like or direct activator of coagulation factor X. The pharmacological modulation of these activities could be potentially important in the control of metastasis growth. However, very limited information is available so far on this issue; it has recently been shown that the direct activator of coagulation factor X is a vitamin K-dependent activity which is depressed by warfarin treatment, not by anticoagulation with heparin or defibrinating enzymes. Whether the inhibition of this peculiar cancer procoagulant is involved in the antimetastatic activity of warfarin is a stimulating hypothesis which needs to be further substantiated.
Clinical Significance of Increased Thromboplastin Activity on the Monocyte Surface – A Brief Review
Authors: Lyberg T.
Published: April 2009

The importance of the blood coagulation sequence as an integral part in the pathogenesis of diseases inside as well as outside the blood vessels is becoming increasingly apparent. Mononuclear phagocytes have important functions in initiation of coagulation by producing several procoagulant substances, including thromboplastin, the potent trigger of the extrinsic pathway. Increasing evidence demonstrates the clinical importance of monocyte and macrophage thromboplastin synthesis in the pathogenesis of a variety of diseases. This review surveys the role of monocyte/macrophage thromboplastin in relation to inflammatory diseases, cancer, disseminated intravascular coagulation and diseases of the blood vessels, thrombosis and atherosclerosis.
Species Specificity of Tissue Thromboplastin
Authors: Janson T.L. , Stormorken H. , Prydz H.
Published: April 2009

The species specificity of thromboplastin (tissue factor) is an important fact to take into consideration when clotting assays or experiments are planned. We have (re)investigated all possible combinations of thromboplastin and plasma from several of the most commonly used species of experimental animals.
Binding of Low-Molecular-Weight Heparin to Aortic Endothelium in Rabbits
Authors: Gensini G.F. , Fortini A. , Lombardi A. , Pesciullesi E. , Pieroni C. , Neri Serneri G.G.
Published: April 2009

The ability of a low-molecular-weight heparin to bind in vivσto the aortic endothelium in rabbits, compared with that of unfractionated extractive sodium heparin (UHEP), was investigated. For this purpose a low-molecular-weight heparin (LMWHEP) fraction (CY 216 A, 4,000–5,000 daltons) and an extractive UHEP (average 17,000 daltons) were labeled with 99mTc and injected (0.2, 0.6, and 1.2 mg/kg) intravenously in groups of 6 rabbits. The binding to endothelium was then measured by counting the radioactivity of samples of abdominal aorta. Both heparins bound to endothelium with a fast, saturable, and reversible binding. No significant difference in the total bound radioactivity was found between the two heparins, suggesting that the investigated LMWHEP retains the ability to bind to the endothelium, contributing to its athrombogenic properties.
Ultrasonic Detection of Platelet Aggregation at Variable Shear Rates
Authors: Machi Junji , Sigel Bernard , Ramos Jose R. , Justin Jeffrey R. , Feinberg Harold , LeBreton Guy C. , Robertson, Jr. Abel L.
Published: April 2009

We have observed that high-resolution ultrasonic imaging can be used to detect and measure the size and sedimentation of large human platelet aggregates formed in vitro. At progressively lower shear rates, individual platelet aggregates grew in cross-sectional area from the limit of ultrasonic detectability of less than 1 mm2 at moderate shear rates to an approximate mean area of 25 mm2 at zero shear. Platelet aggregates tended to sediment at mean shear rates higher than zero shear. At a shear rate of 5.5 s-1, 70% of platelet aggregates had settled, and at 1.6 s-1, 90% had settled to the dependent half of horizontal tubes in less than 15 s. Ultrasonic aggregometry of platelets may be a valuable technique for investigation of platelet dynamics under controlled flow conditions in vitro.
Detection of Drug-Dependent IgG Antibodies with Antiplatelet Activity by the Antiglobulin Consumption Assay
Authors: Conti L. , Fidani P. , Chistolini A. , Francesconi M. , Gandolfo G.M. , Mazzucconi M.G.
Published: April 2009

Drug-induced thrombocytopenia is a common acquired hemorrhagic disorder. In this study 32 patients with drug-induced thrombocytopenia were examined with the anti-globulin consumption assay. Platelet-associated IgG was elevated in 19 of 20 patients that were analyzed. An increase in serum platelet bindable IgG was observed in 24 subjects after the addition of various drugs (acetylsalicylic acid, noraminopyrine, antibiotics, sulfamides, digoxin, heparin and chenodeoxycholic acid). These findings are significant for the presence of drug-dependent platelet antibodies.
Effect of Prostacyclin (Epoprostenol) on the Aggregation of Human Platelets in Whole Blood in vitro
Authors: Saniabadi A.R. , Lowe G.D.O. , Belch J.J.F. , Barbenel J.C. , Forbes C.D.
Published: April 2009

Prostacyclin (PGI2) is a potent endogenous inhibitor of platelet aggregation. The effect of PGI2 on platelet aggregation and disaggregation in whole human blood was studied at 37 °C in vitro. Aggregation or disaggregation was quantified by counting single platelets using the recently developed Ultra Flo 100 Whole Blood Platelet Counter. Aggregation of platelets in whole blood was induced by arachidonic acid (AA, 400 μM), adenosine 5’-diphosphate (ADP, 10 μM), thrombin (0.1 U/ml) and collagen (1 μg/ml). At peak aggregation, each aggregating agent induced about a 90% fall in the number of single platelets counted. When whole blood was pre-incubated with PGI2 (0.5–8 nM), it dose dependently inhibited aggregation of platelets induced by all four aggregating agents. Platelet aggregates induced by ADP or thrombin could rapidly be disaggregated by PGI2 added to blood at peak aggregation. Disaggregation of collagen-induced platelet aggregation by PGI2 was slow and minimal and it was completely ineffective in disaggregating AA-induced platelet aggregates. Unlike platelet-rich plasma, which is routinely used to study platelet aggregation, the present whole-blood method allows red and white blood cells to exert their influences on platelet function, and is an important step towards a physiological state for evaluating the effects of pharmacological agents on platelets in whole blood in vitro and ex vivo.
What’s Provoking Different Aggregation between Arterial and Venous Platelets in the Rat?
Authors: Doni Maria Gabriella , Bottecchia Domenico
Published: April 2009

The present study was designed to clarify the reason why rat platelets obtained from arterial blood show a less marked aggregation than those obtained from venous blood, and to investigate the contribution of the vessel wall to this phenomenon. Incubation of arterial or venous platelet-rich plasma (PRP) with papaverine, a phosphodiesterase blocker, resulted in a more marked inhibition of the aggregation parameters for arterial than for venous PRP, indicating that a cAMP-dependent mechanism is involved. Incubation of PRP in vitro with adenosine deaminase did not significantly modify aggregation. Rats treated in vivo with different doses of acetylsalicylic acid or of tranylcypromine, two cyclo-oxygenase inhibitors, abolished the aggregation differences between arterial and venous PRP. It is suggested that this difference in platelet behavior may be due to a mechanism dependent on a PGl2-like, probably cAMP-related activity in which the heart and/or the lungs may play an important role.
Measurement of Macrophage Cellular Procoagulant Activity
Authors: Muller A.D. , van Dam-Mieras M.C.E. , Hemker H.C.
Published: April 2009

We developed a simple technique for the measurement of the procoagulant activity exposed on the surface of macrophages. The cells are isolated, adhered to plastic surfaces, and assayed in the same device. This approach allows us to study the microcoagulation on the surface of intact macrophages by sensitive and specific clotting tests.
Effect of Ticlopidine on Neutrophil Chemotaxis in Rats
Authors: Cohn Michael , Matzner Yaacov , Eldor Amiram
Published: April 2009

The ex vivo effect of oral administration of ticlopidine on rat neutrophil chemotaxis was evaluated. Rats received either 3 oral doses (100 mg/kg body weight) of the drug, within a period of 48 h, via a gastric tube, or the drug was administered in drinking water for 14 days at a dosage of 75 mg/kg/day. Absorption of the drug was manifested by significant inhibition of adenosine diphosphate- (ADP-)induced platelet aggregation. No impairment of neutrophil chemotaxis toward zymosan-activated serum was observed in the ticlopidine-treated animals. These results indicate that concentrations of ticlopidine that significantly inhibit platelet function in rats are without effect on neutrophil chemotaxis toward zymosan-activated serum.
Evidence of Fibrinogen Breakdown by Leukocyte Enzymes in a Patient with Acute Promyelocytic Leukemia
Authors: Sterrenberg Lydi , Haak Hans L. , Brommer Emile J.P. , Nieuwenhuizen Willem
Published: April 2009

On daunomycin treatment of a patient with promyelocytic leukemia, leukocyte elastase appeared in large amounts in the patient’s blood. Also, the plasma fibrinogen was found to be partially degraded to early, X-like, fibrinogen degradation products. These early fibrinogen fragments were isolated and showed a low anticoagulant activity in a thrombin time test. Early fibrinogen degradation products, produced with leukocyte elastase in vitro, have a similar low anticoagulant activity. In contrast, plasmic degradation products inhibit clotting of fibrinogen to a large extent. Although α2-antiplasmin and plasminogen levels were low, antithrombin III levels were not decreased. The low anticoagulant activity of the isolated fibrinogen fragments, the presence of elastase activity in the plasma – both immunological and amidolytical – and the normal levels of antithrombin III suggest that granulocytic enzymes, whose release was enhanced by the cytostatic treatment, were responsible for degradation of fibrinogen in this patient.
Increased Plasma Proteinase Activity of Mice Bearing the BCL1 Leukemia
Authors: Hart David A. , Cieplak Witold , Muirhead Michael
Published: April 2009

Plasma samples from mice bearing the BCL1 leukemia were shown to express elevated levels of neutral proteinase activity when assayed with radioiodinated casein as a substrate. Increased plasma proteinase activity reached levels 3–4-fold higher than controls. The increased levels of activity did not correlate with the degree of hepatosplenomegaly or the number of tumor cells in the blood. The onset of the increase in plasma activity correlated with the onset of the leukemic phase of the disease. These findings with the murine leukemia may be analogous to recent findings of abnormal proteinase activity in plasma from patients with acute leukemia.
Evaluation of Euglobulin Methods for the Study of Blood Fibrinolytic Activity: Results for Patients with Rheumatoid Arthritis and in the Postoperative Period
Authors: Kluft C. , Cooper P. , Jie A.F.H. , Lowe G.D.O. , Forbes C.D. , Blamey S.L. , van de Putte L.B.A.
Published: April 2009

Euglobulin fractionation is a frequently employed pretreatment of plasma for the determination of fibrinolytic activity. The fractionation procedure suffers from possible in vitro artifacts, e.g., variable precipitation of C1-inactivator. This is illustrated by the following two situations. It is shown that increased amounts of C1-inactivator not related to an increased plasma concentration are present in euglobulin fractions in cases of classic rheumatoid arthritis. Similarly, postoperatively, a disproportional increase in C1-inactivator in euglobulin fractions occurs. In both cases, an artifically reduced fibrinolytic activity is recorded due to increased inhibition by C1-inactivator. This is circumvented and recognized by adding sodium flufenamate or C1s-esterase to euglobulin fractions to uniformly eliminate C1-inactivator. Two specific assays for tissue-type plasminogen activator activity in euglobulin fractions (as C1-inactivator-resistant activator activity and a parabolic rate assay on a synthetic substrate) correlate excellently (r = 0.8728; p < 0.001; n = 108). The first mentioned is corrected for variable endogenous C1-inactivator; the latter assay is found to be insensitive to inhibition by C1-inactivator. It is concluded that with euglobulin methods a misinterpretation of blood fibrinolytic activity is possible in rheumatoid arthritis patients. In the postoperative period, the fibrinolytic shutdown concerns tissue-type plasminogen activator activity; the pattern of the shutdown can be misjudged in using traditional euglobulin methods.
Effect of Latex-Stimulated Granulocytes on Platelet Aggregation in Man
Authors: Zoucas E. , Fäldt R. , Ankerst J.
Published: April 2009

The effect of granulocytes on human platelet aggregation was investigated in vitro. Platelet function was assayed by photometric technique. Incubation of platelets with latex-stimulated granulocytes for 1 h at room temperature resulted in total inhibition of arachidonic acid-induced platelet aggregation. ADP-induced platelet aggregation was suppressed, lacked secondary wave and was pursued by swift disaggregation. Platelet aggregates induced by collagen dispersed faster under the influence of stimulated granulocytes. The present results indicate that granulocytes may play a role in the hemostatic mechanism in man.
Chromatographic Techniques for the Separation of a Thrombocytopoiesis-Stimulating Factor from Aplastic Rats
Authors: Sumereau-Dassin E. , Bourebia J.
Published: April 2009

Thrombocytopoietin seems to be only partially responsible for the regulation of platelet production. We determined precisely the differences between a second thrombocytopoiesis-stimulating factor (TSF2), and thrombocytopoietin (TSF1) and erythropoietin (Epo). Fractionation was carried out, first on a DEAE-cellulose phosphate column and then on a Sephadex G-75 column. Thrombocytopoietic activity in the various fractions was assessed using 75Se-methionine platelet incorporation into normal recipients. Epo concentrations were determined using a radioimmunoassay. We showed that the apparent molecular weight of TSF2 is 14,000 daltons. It differs from TSF1 (48,000 daltons) and from Epo (39,000 daltons). For doses of 8–12 mU Epo/rat, found in whole serum injected, no effect on thrombocytopoiesis was found. On the contrary, a significant effect (p < 0.01) was found when the same quantities of Epo present in the Sephadex G-75 F4’ fraction were injected (2–10 mU/rat). TSF2 can be separated from TSF1 and Epo, using biochemical techniques.
Non-Steroidal Anti-Inflammatory Drugs in Haemophilic Arthritis
Authors: Steven M.M. , Small M. , Pinkerton L. , Madhok R. , Sturrock R.D. , Forbes C.D.
Published: April 2009

Non-steroidal anti-inflammatory drugs are theoretically contra-indicated in the haemophilias but might be useful for those patients with chronic arthritic pain, as long-term strong analgesics are also undesirable. We carried out studies of platelet function and coagulation in 8 normal controls and 7 haemophiliacs while they were taking sequentially benoxaprofen and salsalate. No significant alterations in platelet function, bleeding time or coagulation occurred with either drug. In a subsequent double-blind controlled clinical trial using ibuprofen and placebo 8 of 9 patients had a significant reduction in pain score whilst using ibuprofen without significant change in the frequency of bleeds or the amount of concentrate used. Laboratory measures of coagulation also failed to reveal any adverse effect of the active drug. Non-steroidal anti-inflammatory drugs may be beneficial and may be used with caution in haemophilia.
Correlation between Hepatic Blood Flow and Coagulation Indices in Chronic Active Hepatitis and Liver Cirrhosis Patients
Authors: Violi F. , Alessandri C. , Saliola M. , Caputo V. , Bonavita M.S. , Balsano F.
Published: April 2009

Hepatic blood flow (HBF) has been reported to reflect liver cell mass. HBF was studied in 21 patients with chronic active hepatitis (CAH) and in 20 patients with liver cirrhosis (LC). It was correlated with such indices of liver protein synthesis as serum albumin, Normotest, plasma activity of antithrombin III, prekallikrein, α2-antiplasmin and plasminogen. No correlation between HBF and the examined parameters was seen in CAH. HBF correlated with all the indices of liver protein synthesis in LC, thus suggesting that serum albumin, antithrombin III, Normotest, prekallikrein, plasminogen, and α2-antiplasmin could reflect the residual liver cell mass in LC.