bluuebunny/crossref_metadata_2025 huggingface dataset:
DETECTION AND EFFECTS OF THROMBOMODULIN ACTIVITY IN CRUDE THROMBOPLASTIN PREPARATIONS FROM PLACENTA AND LUNG
Authors: Wiesel M L , Spaethe R , Freyssinet J-M , Tran T , Kolde H-J , Cazenave J P , Grunebaum L , Vavra Z
Published: June 2019

The activation of protein C (PC) by thrombin requires the presence of an endothelial membrane cofactor, thrombomodulin (TM). Activated PC (APC) exerts its anticoagulant activity by degrading factors (F) Va and Villa in the presence of phospholipids and of a vitamin K-dependent cofactor, protein S. Tissue factor (TF) is the essential cofactor of factor Vll/VIIain the activation of factor X. TF is synthetized by several cell lines including endothelial cells. Using a specific TM assay, up to 0.85 units of TM activity could be detected in commercial thromboplastin (TP) preparations from human placenta or rabbit or porcine lung, when the amount of TP was adjusted to contain 1 unit of TF activity. Preparations from brain contained very low amounts, if any, of this activity (< 0.02 TM units). In order to evaluate the effects of the presence of TM activity in some TP preparations, the stability of F V and VIII activities was examined after activation of the coagulation system by these TP in various plasmas. PC deficient plasmas, plasmas lacking F V, VIII or IX and immunoadsorbed PC deficient plasma supplemented with purified human PC (5 Ug/ml) were used. After activation with placenta or lung TP, F V and VIII activities were markedly reduced ( ∼ 90 % reduction) in normal and hemophiliac plasmas, whereas they remained high after activation with brain TP. F V and VIII activities were preserved in protein C deficient plasma after activation by all TP preparations. The same decrease of F V and VIII activities was observed after activation of immunoadsorbed PC deficient plasma supplemented with purified PC with placenta or lung TP only. Preincubation of TP from human placenta with antibodies to human TM raised in laying hens abolished the capacity of this preparation to destroy F V activity of PC containing plasmas. These results establish the presence of TM activity in crude thromboplastin preparations from placenta or from lung. Surprisingly, this anti-coagulant activity seems to be absent from brain. TM from placenta or lung extracts is responsible for the degradation of F V and VIII.
ACTIVATION OF PROTEIN C INDUCES CHANGES IN ITS INTRINSIC FLUORESCENCE
Authors: Mosca A , Viganò D'Angelo S , D'Angelo A
Published: June 2019

Upon activation with either thrombin (T) or thrombin-thrombo modulin complex (T-TM), the zymogen protein C (PC) is transformed into a serine-protease, activated protein C(APC), by release of a small activation peptide. The rate of PC activation changes dramatically with T or with T-TM as a function of the Ca++ concentration in the activation medium, suggesting a configurational change of the zymogen in the presence of Ca++ . It has been shown that Ca++ binding to one single high-affinity binding site of gla-domainless PC is accompanied by a significant decrease of the intrinsic fluo rescence emission intensity of the protein and that the high-affinity binding site is retained following activation of gla-domain-less PC (J. Biol. Chem: 258; 5554, 1983). In the present work we have investigated the fluorescence properties of PC in order to answer the following questions: 1) is there a difference in the fluorescence properties of PC as compared to APC? 2) is there a difference between the conformational changes of PC activated with T or T-TM? From our experimental data we conclude that : a) the fluorescence emission intensity of fully activated PC is about 54% of the PC zymogen fluorescence intensity (λexc 280 nm, λ em 345 nm, 0.6 μuM PC or APC in 20 mMTris-HCl, 0.1 M NaCl, pH 7.8 at 25°C) ; b) during activation of PC (2 μM) with T-TM (150 nM) in the presence of 2 mM Ca++ , there is a good correlation (r=0.959) between fluorescence quenching and degree of PC activation, as measured by the rate of cleavage of the chromogenic substrate S-2238; c) the maximal fluorescence quench of PC activated with T or T-TM are virtually identical. Preliminary data suggest that Ca++ affects differently the fluorescence emission properties of PC and APC. These results suggest that evaluation of the fluorescence properties of PC might represent a valuable tool for the characterization of abnormal PC molecules.
NORMAL PREGNANCY AND DELIVERY IN A PATIENT WITH SEVERE PROTEIN C DEFICIENCY AND PREVIOUS DEEP-VEIN THROMBOSIS
Authors: Bounameaux H , de Moerloose Ph , Vogel J , Reber G , Krahenbuhl B , Bouvier C
Published: June 2019

Congenital protein C (PC) deficiency is associated with thrombophilia. Heterozygotes with about half-normal plasma PC levels may present with venous thromboembolic events usually beginning during adolescence or young adulthood. A 26-year-old swiss woman had experienced an iliofemoral deep-vein thrombosis without obvious etiology six years.ago. In June, 1986 very low levels of PC antigen (25 %) and activity (27 %) were found when she was six-month pregnant. Three other family members (62, 24 and 19-year-old) had PC levels around 50 % but were symptomfree. Because of the post-thrombotic~syndrome and the pregnancy, ambulatory heparin therapy was immediately started in the patient (10-16'000 IU twice daily, s.c.) in order to maintain a plasma heparin level between 0.2 and 0.5 U/ml six hs after the morning injection. Delivery was induced at full-term whilst heparin was stopped for a few hours. Four weeks after delivery anticoagulation was discontinued and, so far, the patient remained symptomfree. The newborn showed no perinatal problem and the PC antigen level assayed in the umbilical venous blood was 22 % (normal range in the literature 18-46 %). Antithrombin III and protein S levels as well as fibtinolytic potential were within normal values in all family members.

Conclusions. 1) Only one out of four heterozygote PC deficient family members had presented with venous thromboembolism. 2) The symptomatic subject had the lowest PC level in the family (activity and antigen around 25 %). 3) This woman experienced an event-free pregnancy and delivery although heparin was started only in the sixth month of pregnancy. 4) Thus, penetrance of the thrombotic trait may be quite variable (and low) amongst PC deficient heterozygotes, an observation which raises the question of the indication of long-term anticoagulation in these individuals. 5) Pregnancy did not affect the PC antigen and activity levels in our patient.
STUDY ON THE EFFECT OF UNFRACTIONATED (UFH) AND LOW MOLECULAR WEIGHT (LMWH) HEPARINS ON THE DETERMINATION OF PROTEIN C ACTIVITY
Authors: Sala N , Fontcuberta J
Published: June 2019

In an attempt to see whether the presence of different heparins affected the determination of protein C activity (APC),this parameter was measured before and during treatment in 23 deep vein thrombosis patients that had been randomly treated with 3 different LMWH (Choay CY-216 and CY-222 and Kabi-2165) and UFH,for 10 days, Very low levels of APC (amidolytic assay that uses thrombin-thrombomodulin to activate the barium citrate eluted PC) were found in those patients receiving UFH and having an APTT more than 3 times that of control, as well as in those patients receiving LMWH CY-216 and having an APTT of only 8 to 10 seconds higher than that of control plasma, In patients receiving CY-222 and Kabi-2165, no significant differences were observed between APC levels before and during treatment, PC antigen (ELISA assay) was normal in all cases, In order to see if these low APC levels were due to interference of heparin with the assay and at which doses, control plasma pool was supplemented "in vitro" with 0 to 2.5 IU/ml (0 to 0,00252) of UFH and with 0 to 3 anti-Xa U/ml of LMWH CY-216, APTT, PCAg, APC and presence of ATI 11 in the barium citrate eluates (immunodiffusion), were determined in all plasma samples before and after treatment with protamine sulphate (PS) at 0,0032, The results showed that UFH, when not neutralized with PS, resulted in low APC values only at doses higher than 0,8 IU/ml, corresponding to an APTT of more than 3 times that of control plasma, LMWH CY-216 at doses above 1 anti-XaU/ml, corresponding to an APTT of only 10 seconds higher than that of control, also produced a gradual decrease in APC values, ATI 11 was clearly visualized in the barium citrate eluates of all those plasma samples having a low APC value, The addition of PS to all samples containing UFH resulted in a complete normalization of APC values, with almost normal AFTT values and disappearance of ATI 11 from the barium citrate eluates, On the contrary, addition of PS to plasma containing CY-216 resulted in low APC values and presence of ATI 11 in the eluates of those samples containing more than 4 antiXaU/ml, whose APTT still was about 10 seconds above that of control.

It is concluded that at therapeutic doses not only UFH but also LMWH CY-216 interfere with the APC assay, probably through binding of hepar in-ATI 11 complexes to barium citrate and neutralization of the thrombin used to activate the barium citrate eluted PC, LMWH CY-222 and Kabi-2165, although increasing the APTT similarly to CY-216, do not seem to interfere with the APC assay, Protamine sulphate, at 0,0032 in plasma, completely abolishes the effect of UFH on APC assay but not that of LMWH CY-216, More studies are being performed to see if higher doses of PS can be used to neutralize the effect of this LMWH.
Effects of Denture Base Thicknesses and Reinforcement on Fracture Strength in Mandibular Implant Overdenture with Bar Attachment: Under Various Acrylic Resin Types
Authors: Tokgoz Selen , Ozdiler Arda , Gencel Burc , Bozdag Ergun , Isık-Ozkol Gulbahar
Published: June 2019

Objective This study aimed to assess the effect of reinforcement, denture base thickness, and acrylic resin types on dynamic and static fracture strength in mandibular implant overdentures with bar attachment.

Materials and Methods One hundred and eight experimental mandibular implant overdentures with bar attachments were fabricated in three main groups, namely unreinforced (control: C), reinforced with unidirectional glass fibers (FR), and Co–Cr cast metal (MR). Each group included denture bases of 2-, 3-, and 4-mm thicknesses and produced with conventional (CA) and high-impact acrylic (HIA) resins. Specimens were thermocycled (5,000 times, 5–55°C) then subjected to a 400,000 cyclic load regime. Unbroken specimens were then loaded until fracture by a universal testing machine. Differences in mean fracture resistance among the groups were compared using the one-way analysis of variance (with post hoc Tukey's honestly significant difference test) and Student's t-tests (α = 0.05).

Results Fracture strength increased significantly when the denture base thickness was increased (p = 0.001). The 2-mm denture base thickness was not enough for reinforcement. The fracture strength of the FR groups was significantly higher than other groups for 3- and 4-mm thicknesses (p = 0.001). The fracture strength of the HIA resin was significantly higher than CA resin in FR groups (p = 0.029 and p = 0.001). MR groups showed the weakest fracture strength.

Conclusions The 2-mm denture base thickness had sufficient fracture strength without reinforcement and a positive relationship between acrylic resin thickness and fracture resistance was found.
Morphological Assessment of Maxillary Sinus Septa Variations with Cone-Beam Computed Tomography in a Turkish Population
Authors: Kocak Nazan , Alpoz Esin , Boyacıoglu Hayal
Published: June 2019

Objective The purpose of this study was to measure and classify sinus septa variables (prevalence, numbers, heights, locations, orientations, and morphology) and to determine the effects of age, gender, and dental status on the presence of septa and also to evaluate the effects of septa on pathological mucosal thickening.

Materials and Methods A total of 2,000 patients were analyzed through conebeam computed tomography (CBCT). The total of 500 maxillary sinuses were included in this study. The number of maxillary sinus septa was determined on axial sections of CBCT images. Their locations, orientations, and morphologies were determined on both the axial and sagittal sections, and their heights were determined only on the sagittal sections. The influence of age, gender, dental status, and pathological mucosal thickening on the presence of septa was statistically analyzed. Mann–Whitney U-test and descriptive statistics were used for statistical analysis.

Results The average height of the determined 287 septa was measured as 7.36 mm. The highest rates of septa location, morphology, and orientation were found, respectively, in the middle region septa (57.49%), completed septa (75.95%), and transverse septa (93.37%). The effect of dental status, age, and gender on the presence of septa was not statistically significant (p > 0.05).

Conclusion These high rates of findings support the importance of CBCT in the diagnosis of the variations of the maxillary sinus septa. Therefore, it is important to evaluate CBCT images of the relevant region to increase the success of surgical interventions in the maxillary posterior region and to eliminate possible complications.
Inhibition of Collagen- or Thrombin-Induced Shape Change of Rabbit Platelets
Authors: Mustard J. F. , Kinlough-Rathbone R. L. , Reimers H. J. , Perry D. W. , Packham M. A.
Published: June 2019

With suspensions of washed rabbit platelets, EGTA inhibits collagen- or thrombin-induced aggregation but does not inhibit shape change caused by these agents. Addition of apyrase or creatine phosphate/creatine phosphokinase (CP/CPK) to a suspension of washed platelets reduces the extent of collagen-induced aggregation but does not inhibit shape change. Combinations of EGTA with apyrase, CP/CPK, acetyl salicylic acid (ASA) (500 μM) or sulfinpyrazone (300 μM) inhibit collagen-induced shape change. Apyrase and ASA together also inhibit collagen-induced shape change. None of these combinations of inhibitors inhibits thrombin-induced shape change completely, although apyrase or CP/CPK cause partial inhibition. With thrombin-degranulated platelets, collagen induces shape change and a small increase in light transmission. This effect of collagen is inhibited by ASA but not by CP/CPK. The addition of collagen to ASA-treated platelets causes platelet shape change although aggregation does not occur. Addition of collagen to a mixture of thrombin-degranulated and ASA-treated platelets results in shape change and aggregation. It seems likely that endoperoxides formed by the thrombin-degranulated platelets in response to collagen cause shape change and aggregation of the ASA-treated platelets which are unable to form endoperoxides. These observations demonstrate that collagen-induced shape change of rabbit platelets involves two different mechanisms, one of which is inhibited by CP/CPK (and hence is probably caused by released ADP) and one which is inhibited by ASA (and may involve endoperoxide formation). Although thrombin can induce shape change by releasing ADP, it can also induce shape change through a mechanism which is independent of adenine nucleotides release and is not inhibited by ASA.
Release of Fibrinolytically Active Compounds During Platelet-UK Interaction
Authors: Koch M. , Binder B. , Auerswald W.
Published: June 2019

In view of contradictory reports concerning the influence of platelets on the fibrinolytic activity in vivo and in vitro, we studied the effects of washed platelets on the fibrinolytic activity of added urokinase (UK). Different amounts of UK (0.6 to 2.5 CTA units per ml, purified UK-preparation) were mixed with washed platelets numbering 1,000 to 1,000,000,000 per ml. The fibrinolytic activities of these mixtures as well as of the platelet-free supernatants there of were tested on native and heated fibrin plates. Neither UK nor platelets alone nor the mixtures of both revealed any fibrinolytic activity on heated fibrin plates. In addition, no plasminogen activator activity of the native platelets could be detected.

The presence of more than 10,000,000 platelets per unit UK suppressed the kinases’s activity progressively as the platelet number increased. With less than 10.000.000 platelets per unit UK the kinase activity was augmented to a maximum when the platelet count reached about 200,000 per unit UK. The supernatants of the platelet-UK mixtures reflected the same activities as the mixtures. Using plasmin instead of UK in the mixtures with platelets similar results were obtained. In control experiments incubating platelets with albumin- or buffer-solutions the supernatants were without effects. Furthermore at no of the mentioned concentrations of UK added to platelets were any effects found on their count, their adherence to glass, and their spreading ability.

In preliminary investigations supernatants from platelet-UK mixtures were gel fractionated on Sephadex G-150, to determine the presence of fractions with inhibiting and/or potentiating effects on fibrinolysis. An inhibiting fraction of low mol. wt. and probably two potentiators of higher mol. wt. have thus far been found.

Supp. by a Grant of the Austr. Fund f.t. Promot. of Scient. Res. (Proj. Nr. 1800).
A Smaller Molecule SK-Reactive Protein (Plasminogen-Proactivator) Derived from the Macromolecule of Human Plasma Fraction I.
Authors: Okamoto U. , Yamamoto J.
Published: June 2019

The SK-reactive plasminogen-proactivator reported in detail by previous workers assumed a macromolecule protein though still impure. A smaller molecule proactivator highly purified is described in the present paper.

Fraction I of human plasma was chosen as staring material after preliminary studies. The macromolecule obtained by gel filtration had low specific activity of SK-reactive protein (proactivator) but little UK-reactivity, showing constantly a large molecular weight by repeating gel filtration. The successful purification of proactivator was achieved by Lysine-Sepharose affinity chromatography, using as eluant t-AMCHA (fibrinolysis inhibitor) which was found suitable.

The proactivator fraction thus obtained showed the high sensitivity to SK, other proteins being removed satisfactorily and the specific activity being increased extremely. Even a trace of plasminogen was not detected. Molecular weight of the proactivator was found 98,000 by gel filtration.

The results indicate that the smaller molecule proactivator described is a basic entity of SK-reactive proactivator of plasminogen.
Pulmonary Endothelial Cells / Metabolism of Vasoactive Substances
Authors: Ryan J. W. , Ryan Una S.
Published: June 2019

The lungs metabolize a variety of vasoactive substances, including bradykinin (BK), angiotensin I (AT I), PGE2 and F2α, norepinephrine, 5-HT, 5’-ATP and 5’-AMP. In contrast, the lungs od not metabolize angiotensin II (AT II), PGA2, histamine and epinephrine. Of the substances metabolized, all (with the possible exceptions of the prostaglandins) are processed primarily by the pulmonary endothelial cells. Furthermore, the means by which the substances are processed suggest that endothelial cells determine the vasoactive substances allowed to enter the systemic arterial circulation. BK is inactivated while AT I is converted to its potent homolog, AT II. AT II enters the arterial circulation. The metabolism of BK and AT I may be effected by the same enzyme. Pulmonary endothelial cells are a rich source of thromboplastin, an enzyme capable of degrading BK and AT I. However, the relationship of thromboplastin to the fates of these hormones is not clear : The metabolic products produced are not those produced by intact lungs nor by endothelial cells in culture. In addition, thromboplastin degrades substances (e.g. AT II), which are not degraded by intact lungs. Possibly the extrinsic clotting system plays a role when activated but not under physiologic conditions.
Improved Technique to Produce Endothelial Injury by Laser Beam without direct Damage of Blood Cells
Authors: Kovács I. B. , Sebes A. , Trombitás K. , Gsalay L. , Görög P.
Published: June 2019

Ultrastructural study of microcirculatory thrombus induced by He-Ne laser and application of energy absorbing dye Evans blue demonstrated severe endothelial damage covered by extreemly disintegrated platelets. To exclude the direct effect of laser beam to platelets and red cells, we used the technique of Baez for the perfusion of intact mesentery microvasculature of the living rat in situ. During laser irradiation arteries deriving from the ileocolic artery were filled with albumin solution containing Evans blue, thereafter the blood circulation was restored and thrombus formation was investigated at the site of irradiation. According to the ultrastructural findings, thrombus formation is based on the interaction between the exposed subendothelium and intact platelets. Additional advantage of this technique that lower dose of Evans blue is sufficient.
Effect of Aspirin and Methysergide During Acute Intracoronary Thrombosis in the Dog
Authors: Kordenat R. K.
Published: June 2019

An occluding intracoronary thrombus was produced in two groups of dogs by placing a thrombogenic wire into the anterior descending coronary artery, by catheter technique (under x-ray control). One group of six dogs was pretreated with methysergide (100 micrograms/kg, i.v.-two hours before wire placement) and aspirin (60 mg/kg, per os.-daily for three days). The other group of seven dogs served as the control. Central aortic blood pressure (CAPB), heart rate (HR), S–T segment elevation and Q wave depression (lead V4 in the electrocardiograph) were measured before, one and three hours after angio-graphically verified occlusion. Arterial and coronary venous lactate (Lac, pyruvate (PYR), creatine phosphokinase (CPK) and serum electrolyte (Mg, Ca, K and Na). Concentrations were also measured during these times. There were no S–T or Q wave changes, at any time, in five of the six pretreated dogs over the observed time, and a fifty percent reduction of the S–T amplitude was found in the dog that did develop these signs of injury and infarction, at the third hour. All control dogs showed S–T and Q wave changes by the third hour. The mean CAPB dropped significantly (p < 0.01) in the control but not in the treated group. There were significant elevations (p < 0.05) of CV concentrations of Lac and K in the control group at the third hour. There were no significant changes in concentrations for these biochemical variables in the pretreated group. The cardiac dynamics and biochemical integrity appeared to be sustained by these pharmaceutical agents in the early stages of acute coronary thrombosis.
Enhancement of ADP-Induced Platelet Aggregation by Isometric Hand-Grip Excercise in Sclerotic Patients and its Prevention by EG-626, cAMPPDE Inhibitor
Authors: Sano T. , Motomiya T. , Yamazaki H. , Shimamoto T.
Published: June 2019

We have reported an enhancement of ADP- and epinephrine-induced platelet aggregation in acute stage of thrombosis (TDH suppl. 60, 213, 1974). In such enhancement, a role of cyclic AMP in platelets is important. Recently Shimamoto and Hidaka found a potent cAMP phosphodiesterase inhibiting effect in a new synthetized drug, phthalazinol (EG 626). It inhibited primary and secondary aggregation in vitro in 1 ~ 5 μg/ml of final concentration. So we examined an effect of EG 626 on platelet aggregability induced by isometric hand-grip exercise. Isometric hand-grip exercise at 50% maxial voluntary contraction (Mod. Concept. Cardiovasc. Dis. 41, 11, 1972) was performed for 2 minutes, in 15 coronary herart disease, 13 cerebral artieriosclerotic disease, 15 essential hypertension and 15 control subjects. ADP-induced platelet aggregability was assessed before and after exercise by a new method (TDH 25, 524, 1971). Also heart rate, blood pressure and systolic time intervals were recorded. An enhancement of platelet aggregability to ADP by exercise was disclosed significantly (p < 0.01) in coronary and cerebral sclerotic patients. The enhancement was prevented when the patients were orally pretreated with EG 626, 300 mg 1.5 hours before exercise. PEP/ET value on the exercise was significantly (p < 0.05) reduced with EG 626 pretreatment, suggesting enhancement of cardiac contractility by EG626.
Coagulation Inhibitors Studied with Chromogenic Substrate
Authors: Abildgaard U. , Lie M. , Teien A. , Ødegård O. R.
Published: June 2019

The rapid amidolysis of the chromogenic substrate Bz-Phe-Val-Arg-pNA by thrombin (Svendsen & al. Thromb. Res. 1, 267, 1972) provides a useful tool for the study of coagulation inhibitors. With purified reagents, reversible inhibition of the reaction can be demonstrated with 0.01 U/ml of heparin. The inactivation of thrombin by antithrombin III (At-III) is accelerated by 0.001 U/ml of heparin, making it possible to assay small amounts of heparin. The amidolytic assay system has also been used to study the competition between thrombin and factor Xa for At-III.

The sensitivity and specificity of rapid amidolytic methods for assay of the following plasma activités will be reported:

1) At-III activity (contaminating heparin neutralized).

2) Exogenous heparin (during heparin treatment).

3) Combined effect of At-III and exogenous heparin.

4) At-III in the presence of optimal concentrations of heparin.
Affinity of Antithrombin II/III to Insolubilized Heparin
Authors: Thaler E. , Schmer G.
Published: June 2019

Five heparin fractions of different molecular weight range were obtained from commercial sodium heparin (Sigma) by gel chromatography on Sephadex G-200. Each fraction was bound separately to Biogel A-15 m by the cyanogen bromide reaction. Microcolumns containing equal amounts of the individual heparin agarose batches were prepared. A protein fraction from human plasma containing antithrombin II/III but no fibrinogen, which was obtained by polyethylene glycol precipitation, was passed through the columns. After extensive washing with 0.15 and 0.3 M buffered sodium chloride antithrombin was eluted with 1.0 M buffered sodium chloride. The uptake of antithrombin did not differ greatly in all five heparin agarose preparations. However, the amount of antithrombin eluted with 1.0 M NaCl varied considerably depending on the insolubilized heparin fraction. Almost no antithrombin activity was eluted from the agarose grafted with the highest molecular weight heparin, while all of the antithrombin was recovered from the agarose with the intermediate molecular weight heparin.

Our findings of different affinities of antithrombin to insolubilized heparin in dependance of its molecular weight suggest similar implications for the practical use of heparin in anticoagulant therapy.
Action of HL-A Specific Antibodies on Platelets in Vitro
Authors: Heinrich D. , Kessler C. , Stephinger U. , Kunkel W. , Mueller-Eckhardt C.
Published: June 2019

Refractoriness to platelet transfusion in thrombocytopenic patients often is due to HL-A isoimmunisation. HL-A antibody-induced platelet alteration in vivo is associated with a reduction of platelet survival.

Action of HL-A specific antibodies on platelets in vitro was studied applying serological (absorption/elution-experiments; micro-complement fixation), morphological (platelet spreading, electron microscopy) and functional parameters (clot retraction, platelet agglutination, 14C-serotonin uptake and 14C-serotonin release).

Results: Incubation of platelets (PRP) with HL-A specific antisera induced a specific platelet agglutination with degranulation and 14C-serotonin release, furthermore a specific inhibition of 14C-serotonin uptake and clot retraction. Experiments with Prostaglandin E15 Apyrase, Heparin, ASA and EDTA in connection with a HL-A specific LDH-liberation from platelets suggest a lytic, complement-dependent action of HL-A antibodies on platelets in plasma (PRP).

Experiments with washed platelets and HL-A specific eluates (D. Heinrich et al.: Vox Sang. 27, 310, 1974) indicate a second, nonlytic action of HL-A antibodies on platelets. Cofactors of the latter reaction are Ca++, fibrinogen and thrombin.
Inhibition of Virus-Induced Platelet Aggregation by Treatment of Platelets with Neuraminidase
Authors: Chernesky M. A. , Larke R. P. B.
Published: June 2019

Washed suspensions of rabbit or human platelets aggregate and release their constituents (adenine nucleotides, serotonin and lactic dehydrogenase) when mixed with Newcastle disease virus (NDV) or Sendai virus (paramyxoviruses) in a stirred system at 37° C. Treatment of rabbit platelets with chromatographically purified neuraminidase which removed 10–20 ug of sialic acid/101 platelets reduced, by more than 95%, platelet aggregation and release of constituents by virus; treated platelets were as responsive to stimulation with ADP or thrombin as were control platelets. Virus, which normally becomes associated with aggregated platelets, failed to attach to neuraminidase-treated platelets and was recovered in platelet supernatant fluids. Subsequent aggregation of these mixtures of virus and neuraminidase-treated platelets with thrombin failed to trap NDV in platelet aggregates. Electron microscopy (carbon replica and thin-sections) revealed an absence of virus attachment on surfaces of platelets treated with neuraminidase.

These data indicate that a receptor substance containing sialic acid present on the platelet surface is necessary to enable paramyxoviruses to attach and induce platelet aggregation and release of platelet constituents.
Distinction of Plasma Inhibitor of Activator-Induced Clot Lysis from Antiplasmins
Authors: Aoki N. , Matsuda M. , Moroi M. , Yoshida N.
Published: June 2019

A fraction of human plasma prolongs the activator-induced clot lysis time and inhibits plasminogen activation by the plasminogen activators derived from various sources (urine and tissues). This fraction, designated as antiactivator fraction, was separatid from antiplasmin fractions (α2-macroglobulin and α1-antitrypsin) by gel filtration and affinity chromatography on Sepharose coupled with IgG of antiserum to α1-antitrypsin. Anti-activator fraction thus obtained exerted little antiplasmin activity but inhibited strongly activator-induced clot lysis.

Inhibitory effect of plasma on urokinase-induced clot lysis (antiactivator activity) was assayed in various diseases and compared with antiplasmin activity. No correlation was found between the two activities, and it was concluded that the two activities are independent and are ascribed to two different entities.
Fibrinolysis Versus Fibrinogenolysis: The Specificity of Human Vascular Activator (VA) as Compared to Urokinase (UK) and Streptokinase (SK)
Authors: Lipinski B. , Gurewich V. , Hyde E.
Published: June 2019

Activation of fibrinolysis by venous occlusion or exercise was shown previously not to cause degradation of plasma fibrinogen either in vivo or in vitro. The proteolytic effect of activated fibrinolysis was evident only when substrate was in a solid phase (fibrin or precipitated fibrinogen). In this study, clotted and unclotted plasma was incubated at 37° C for 18 hours with 3 activators. SK and UK induced degradation of both fibrin and fibrinogen, whereas VA was active exclusively on the fibrin substrate. Moreover, VA did not alter the mobility and concentration of 2 fibrinogen fractions found on plasma electrophoresis in 3.5% SDS-polyacrylamide gel. However, when VA was incubated with isolated fibrinogen (plasminogen rich) degradation took place. The addition to this purified system of normal serum or plasma diluted up to 100-fold, inhibited fibrinogenolysis but not fibrinolysis. It is concluded from these experiments that human blood contains a specific and highly potent inhibitor which forms a complex with VA. Dissociation of this complex requires a solid phase thus allowing plasminogen to be activated. This inhibitor appears to be highly specific for VA. It is postulated that direct fibrinogenolysis in man is not induced by naturally occurring plasminogen activators. The catabolism of fibrinogen may involve other proteolytic enzymes, or alternatively an intermediate solid phase.
A Physiological Study on the Releasing Mechanism of Plasminogen Activator from the Vascular Wall
Authors: Kitaguchi H. , Izaki S.
Published: June 2019

Some precise information is described of the releasing mechanism of plasminogen activator from the vascular wall. Using the isolated hind leg of dog perfused with Hank’s solution under the physiologically controlled conditions by a modified Dale Schuster type circulation system, the activator activity and flow rate of the perfusate were carefully estimated every fifteen seconds after administering the vasoactive agents of different kinds.

A transient but steep rise of the activator activity was definitely observed when some vasodilators (acetylcholine, histamine, bradykinin and eledoisin) and the strong vasoconstrictors (adrenaline, noradrenaline and vasopressin) were administered. However, such effect was hardly observed when other dilators (isoproterenol and papaverine) and a weak constrictor (serotonin) were given. Concerning the minimum effective dose and the total sum of the activator released effect of the active dilators was found clearly predominant compared with the active constrictors, In addition, it was indicated that, in term of releasing the activator, the constrictors required Ca ion but the dilators did not.

Results obtained imply that the activator releasing is triggered by the strong vasoconstriction, and more predominantly by a Ca ion independent membrane reaction due to the vasodilators without accompanying the vasodilatation.
The Use of Logistic Analysis to Distinguish between Normal and Pre-Eclamptic Patients
Authors: Howie P. W. , Purdie D. , Begg C. , Forbes C. D. , Prentice C. R. M.
Published: June 2019

Tests of coagulation and fibrinolysis were performed in 20 patients with severe preeclampsia and in 20 normal pregnant women. Compared with the normal patients, the women with severe pre-eclampsia had raised factor VIII, increased cryofibrinogen and reduced platelet counts. Despite increased resistance to urokinase-induced fibrinolysis, the pre-eclamptic women had lower plasminogen and increased serum and urinary F.D.P. levels. These results suggested that intravascular fibrin deposition was a feature of severe pre-eclampsia. In each test, the range of values in the pre-eclamptic women overlapped with the controls, so that no single test indicated whether intravascular coagulation was present in every case of severe pre-eclampsia. By the use of logistic analysis, it was possible to demonstrate that an abnormality of the coagulation and fibrinolytic systems was present in every case of severe pre-eclampsia. In 10 patients with moderate pre-eclampsia, the severity of the coagulation abnormality was intermediate between the severe cases and the controls.

By sequential logistic analysis, it may be possible to anticipate the phase of clinical deterioration and permit delivery before the onset of fetal death. The haemostatic abnormalities would appear to be a constant and inevitable feature of pre-eclampsia.
Selective Release of Serotonin from Human Platelets by X-537 A, Acting as an Ionophore for Serotonin
Authors: Wörner P. , Brossmer R.
Published: June 2019

The ionophore X-537 A facilitates the permeation of calcium through membranes. Human platelets exposed to X-537 A undergo a release of serotonin, which has been attributed to an increase in the concentration of cytoplasmic calcium, mediated by X-537 A. However, at a low concentration of X-537 A, platelets release serotonin but one cannot observe a release of heparin-neutralizing activity (PF4) and adenine nucleotides, an activation of clot-promoting activity (PF3), or a significant uptake of 45calcium into platelets. Electron micrographs of platelets after exposure to X-537A do not exhibit the alterations known to be coupled with the release reaction, despite a considerable release of serotonin. Two-phase partition studies demonstrate that X-537A is able to extract serotonin into an organic phase. In summary, these results indicate that X-537A causes a selective release of serotonin by transporting it through membranes. Only at high concentrations of X-537A can one establish an uptake of 45calcium by platelets and a release of PF4 and adenine nucleotides in addition to that of serotonin.

(Supported by “Deutsche Forschungsgemeinschaft, Bonn”, Sonderforschungsbereich 90, “Cardiovasculares System”.)
Acquired Storage Pool Deficiency in Platelets during DIC
Authors: Pareti F. , Capitanio A. , Chantarangkul V. , Mannucci P. M.
Published: June 2019

During DIC, circulating platelets are exposed to thrombin and other aggregating agents causing the release reaction. It is conceivable that “stimulated” platelets may have altered functions which contribute, with the decrease in number, to the bleeding tendency of these patients. Platelet aggregation, adenine nucleotides (AN) content and release, serotonin (5 HT) content, uptake and metabolism have been investigated in a patient with an acute bleeding tendency associated to laboratory findings suggesting the occurence of DIC. Secondary aggregation to ADP and adrenaline was absent; collagen aggregation was also defective. Release of AN induced by different collagen concentrations was much lower than in the normal controls. Levels of AN were reduced (mainly ADP) ; ATP/ADP ratio was higher than in control platelets. Since AN of the metabolic pool were normal, the deficiency is due to lack of AN of the storage pool. 5 HT content and the ability to take up the exogenous amine was also reduced in the patient’ platelets. Their prolonged incubation with 14 C 5 HT resulted in a progressive loss of radioactivity in plasma, while normal platelets, in the same conditions, stored the amine throughout the incubation period. This abnormal behaviour has been observed in platelets of patients affected by congenital storage pool deficiency (SPD) and is caused by abnormal platelet metabolism of the amine. The abnormalities observed in this patient with DIC are stikingly similar to those present in congenital SPD and are likely to be produced by in vivo exposure to aggregating agents followed by release of storage granules.
Capillary Thrombosis as a Factor in the Evolution of Traumatic Brain Lacerations
Authors: Coccheri S. , Testa C.
Published: June 2019

In a group of patients with Traumatic Brain Laceration (TBL) studies on blood coagulation and platelet function were performed in blood samples obtained during angiography from the omolateral carotid artery and jugular vein. Intraoperatory microbiopsies were also performed during neurosurgical operations in patients with TBL at different stages of evolution. In the acute stages of TBL necrosis of the endothelium and extensive micro-thrombosis with platelet material occurs in the capillaries around the damaged area. In the blood obtained from the jugular vein a fall in platelet count, platelet materials and positive paracoagulation tests can be observed.

These data suggest that a process of regional intravascular coagulation occurs after TBL around the damaged area. Resulting microthrombosis may be regarded as a significant factor in the pathogenesis of acute ischemic intracellular edema in neurotraumatology.
Quick-Time Standardization
Authors: Canaveri Martínez A. A. , Alonso B. , Touceda M. , Pavlovsky M. , Bergna L. J.
Published: June 2019

Ten different kinds of thromboplastin were studied from: A) Rabbit brain: 1) Britania, 2) Biochem, 3) Rivero, 4) Dade, 5) Simplastin and 6) Hyland; B) Pig lung: Geigy; and C) Human brain: 1) Academy of Medicine, Buenos Aires, and 2) Municipal Hematology Institute. They were compared with three International Standards: British Comparative Thromboplastins: BCT (Manchester), 69/223 and 70/178 (National Institute for Biological Standards and Control, London).

The aim was to learn about the use of oral anticoagulants as there seems to be a lack of agreement in the results obtained at different centres due to the variety of thromboplastins used, also to the different meanings given to the words “therapeutical range”. Four or more different thromboplastins were studied the same day in 1 to 5 normals and 6 to 20 patients.

The relative sensitivity of the different thromboplastins was establish. The sensitivity, the “ratio” and the percentage of activity varied markedly according to the kind of thromboplastin used. The difference was more marked with decreasing anticoagulation levels.
Comparative Hemorheological and Biochemical Studies of a Bovine Fibrinogen
Authors: Copley A. L. , King R. G. , Blombäck B.
Published: June 2019

Among numerous fibrinogen (Fg) preparations of different mammalian origins (human, bovine, sheep, rabbit, cat) in measurements of viscous resistance -VR- (torque values, τ, dyne, cm) of surface layers (SLs), we found as an exception a bovine Fg, FgSM (Schwarz-Mann, Orangeburg, N.Y. Lot # Y1013), which did not show measurable VR at shear rates (SRs) from 10-3 to 10-1 sec-1 without prior application of high shearing forces (hSF). This led to biochemical characterization, in which FgSM did not exhibit any significant difference in chain structure, as compared with highly purified Fg showing high τ, indicating that a dialysable component in the FgSM was responsible for the inhibition of VR. Our biochemical studies could not detect significant differences between the FgSM and Fg from other sources. A hSF at 1000 sec-1 for 3 min was then applied prior to the rheological tests at low SF from 10-3 to 10-1 sec-1. This procedure always resulted in significant increases in VR of SLs of all Fg preparations, including the FgSM. High shear, which exists at the vessel wall in vivo, is particularly high in the microcirculation and is also augmented in vortex and disturbed flow at sites of branchings, bends and bifurcations in the vascular system. The hSF may contribute to the initiation of thrombus formation due to the proposed progressive adsorption of Fg, layer upon layer, at these sites (Copley, Biorheol. 8, 79, 1971; Microvasc. Res. 8, 192, 1974). A further hypothesis is introduced in which the polymerization sites of the Fg molecule are unfolded by the hSF at the vessel wall, resulting in intravascular polymerization of Fg

(Aided in part by Office of Naval Research Contract # N00014-75-C-0222 )
Kinetics of Platelet Adhesion to Artificial Surfaces in Vitro
Authors: Brash J. L. , Feuerstein I. A.
Published: June 2019

Adhesion of platelets to glass, collagen-coated glass, albumin-coated glass, polystyrene, sulfonated polystyrene and a segmented polyurethane, has been studied in vitro. The apparatus is of the Couette flow type and allows close control of fluid shear and diffusional factors. Suspensions of washed pig platelets constitute the basic platelet medium. This can be modified by adding back red cells and specific plasma proteins in varying concentration and the platelet concentration can be varied without compromising viability. Adhesion is measured by radiolabelling methods.

In the absence of red cells, low levels of adhesion were seen on all surfaces with saturation occurring at 4 to 6 platelets/1000 μ2 in 2 to 4 minutes. In the presence of red cells adhesion was much greater. Collagen was the most reactive surface and adhesion data was consistent with a platelet diffusivity 10 to 100 times that predicted by Brownian motion. The diffusivity was dependent on shear rate and hematocrit. All other surfaces showed a 2-fold increase in adhesion compared to the values without red cells. However adhesion was independent of hematocrit above 10% and reached a constant value of about 12 (less for albumin monolayer) in 2 to 10 minutes.
In Vitro Prothrombin Synthesis - The Vitamin K-Dependent Carboxylation of a Prothrombin Precursor
Authors: Suttie John W. , Esmon Charles T. , Grant Gregory A. , Sadowski James A.
Published: June 2019

Prothrombin is synthesized from a liver microsomal precursor which has now been characterized. The precursor contains functionally active thrombin and can be degraded by thrombin, Xa, or snake venoms to yield products which appear to be identical to those obtained from prothrombin. The molecular weight and amino acid composition of the precursor are similar or identical to prothrombin, but it lacks the calcium-binding sites needed for (Ca++, phospholipid) accelerated activation. In the presence of added vitamin K, an in vitro microsomal preparation incorporates 14

into microsomalbound precursor. It has been demonstrated that this incorporation is at glutamic acid residues in the amino terminal portion of the protein to form γ-carboxygiutamic acid residues. Both 14HC03 incorporation and formation of prothrombin (2-stage activity) in this preparation are dependent on: the presence of precursor in the microsomal preparation; an energy source; O2;

NADH (NADPH); and vitamin K. Both systems are inhibited by chloro-K, but not significantly by coumarin anticoagulants. However, microsomal preparations obtained from warfarin-treated rats are not as responsive as those obtained from vitamin K-deficient rats. The same microsomal preparations that form prothrombin will also catalyze the conversion of phylloquinone to its 2,3 epoxide. It has been suggested by Willingham and Matschiner (Biochem. J. 140, 435) that this epoxidation is an obligatory process coupled with the action of vitamin K in the conversion of precursor to prothrombin. Requirements for the two systems appear to be very similar, and in vitro conditions which will result in prothrombin production, but not epoxidation, have not yet been demonstrated.

(Supported by NIH Grant no. 14881.)
High Level of Fibrinolysis and Low Factor XIII in Erosive Haemorrhagic Gastroduodenitis
Authors: Nilsson I. M. , Bergentz S.-E. , Hedner U.
Published: June 2019

Erosive haemorrhagic gastroduodenitis was found to be combined with high fibrinolytic activity of the gastric juice. This activity was due to a plasmin-like enzyme and not to other gastric proteolytic enzymes. No increase in fibrinolytic activity could be demonstrated in blood, but the values found for fibrinogen, plasminogen and α2M were low. A high content of FDP was found in serum. A markedly decreased content of factor XIII was found with the dansylcadaverine method. Platelet count and other coagulation components were normal. These findings were interpreted as local fibrinolysis in the diseased parts of the gastrointestinal canal. The bleeding stopped after administration of A MCA (Cyclo-kapron® ) and factor XIII concentrate. The results indicate that the high local fibrinolytic activity in the stomach together with the low content of factor XIII contributes substantially to the increased bleeding tendency in erosive gastritis. This may lead to a revision of the treatment of such cases.
Molecular Shape of Fibrinogen in Solution
Authors: Marguerie G. , Stuhrmann H.
Published: June 2019

Neutron small angle scattering in various H2O/D2O mixture was carried out for investigating the structure of fibrinogen in solution. Analysis of the scattering pattern in terms of multipoles yields an overall shape which can be described by a banana-like model. The maximum segment density is only a quarter of that encountered with compact globular proteins. This suggests that fibrinogen is rather loosely packed and seems to be an intermediate representative between compact globular proteins and statistical coil. The proposed structure is compared with physicochemical and electron microscopic properties of fibrinogen.