bluuebunny/crossref_metadata_2025_split huggingface dataset:
RELATIONSHIP BETWEEN VESSEL WALL 13-HODE PRODUCTION AND SUBENDOTHELIAL BASEMENT MEMBRANE THROMBORESISTANCE: INFLUENCE OF SALICYLATE
Authors: Weber E , Haas T A , Hirsh J , Buchanan M R 
Published: August 2018

In previous studies, we have reported that i) the basement membrane (BM) underlying endothelial cells was initially throm-boresistant; ii) 13-hydroxyoctadecadienoic acid (13-HODE) synthesized by endothelial cells from linoleic acid via the lipoxygenase pathway, contributed to the thromboresistance of the endothelium; and iii) salicylate (SAL) increased injured vessel wall thrombogenecity. Therefore, we performed studies to determine the relationship between injured vessel wall thrombogenecity, vessel wall 13-HODE and cAMP levels, and salicylate treatment. Injured vessel wall thrombogenecity was measured as the number of H-adenine platelet (3H-PLT) adherent to the subendothelial BM exposed by air injury in carotid arteries of rabbits treated with 0 or 100 mg/kg of SAL bid, given orally2. Vessel wall 13-HODE was measured as the amount of 13-HODE/cm produced by the vessel wall following stimulation with 10μ/M linoleic acid, and measured by HPLC. Vessel wall cAMP levels were measured by RIA. Four hours after air injury, there was 25.4 ± 2 3
2H-PLT/cm2 of exposed BM. This was associated with 15.9 ng/cm2 of 13-HODE and 308 pM/cm2 of cAMP (Table 1). In contrast, in rabbits treated with SAL, there was a 2-fold increase in platelet adhesion onto the injured carotid arteries. The increase in platelet adhesion was associated with a 65% decrease in 13-HODE production by the vessel wall and a modest (20%) decrease in cAMP level.We conclude that the lipoxygenase derived linoleic acid metabolite, 13-HODE contributes not only to the thromboresis-tance of the endothelium, but also to its underlying basement membrane.
THE EFFECT OF ARTERIAL DE-ENDOTHELIALIZATION ON IN VIVO AND EX VIVO PLATELET FUNCTION TESTS IN THE BABOON
Authors: Kotze H F , Badenhorst P N , du A , Heyns P , Heyns P , van Wyk V 
Published: August 2018

The effect of endothelial cell injury on platelet function was evaluated in eight baboons with a normal vasculature. Endothelium was removed with a balloon catheter. On each baboon, the left carotid artery was de-endothelialized on day 0 and the right carotid artery and abdominal aorta on day 7. Mean platelet density (MPD; gm/ml), circulating platelet aggregate ratio (CPA), the number of electron-dense bodies per platelet (DBP) , and the plasma concentration (ng/ml) of platelet factor 4 x(PF4) and beta thromboglobulin (bTG) were determined on day -7 (baseline). These ex vivo measurements were repeated on days 1, 9 and 16. The mean lifespan (MPLS) and sites of sequestration of In-111-labelled platelets were determined from day 7 onwards. The results of the ex vivo platelet function tests were:De-endothelialization of only the left carotid artery did not affect ex vivo platelet function. More extensive denudation decreased MPD, and increased CPA, PF4 and bTG. CPA were still abnormal 7 days after the insult. MPLS, 120±21 hours, was shorter (p<0.05) than normal, 145±15 hours. The sequestration pattern of senescent platelets was normal. We conclude that a decrease in the MPD, an increase in CPA, bTG and PF4, and a shortened MPLS are the most sensitive tests for in vivo platelet activation.
PATCH ANGIOPLASTY INCREASES PLATELET DEPOSITION FOLLOWING CAROTID ENDARTERECTOMY
Authors: Meek A C , Jarvis P , Harper R A , McCollum C N 
Published: August 2018

Patch angioplasty with vein or Dacron may be required to prevent narrowing when the arteriotomy is closed following carotid endarterectomy. We studied the effect of such patches on intraluminal thrombus formation by measuring radiolabelled platelet uptake in patients following simple closure and patch angioplasty.Following unilateral carotid endarterectomy in 33 patients, the arteriotomy was closed by direct suture in 23, Dacron patch in 6 and saphenous vein patch in 4. Autologous 111In-platelets were infused on the second postoperative day and platelet uptake over the carotid measured on daily gamma camera images for 3 days. Radioactivity over the operated and contralateral carotids were compared as the Carotid Uptake Ratio.Mean (±sem) counts per gamma camera cell at 24 hours in the operated carotid of 43.6±3.0 were consistently higher than the reference artery of 35.4±2.4 (p<0.001). The overall carotid uptake ratio was 1.21±0.04 with that of 1.41±0.07 in patch angioplasty significantly higher than 1.14±0.04 found following standard arteriotomy closure (p<0.01). All 10 patch angioplasties were easily visible as "hot spots" on gamma camera compared to only 11 out of 23 with simple closure but there was no significant difference between platelet uptake with vein or Dacron patches with ratios of 1.47±0.35 and 1.37±0.15 respectively (p>0.5).The greater local platelet accumulation with patch angioplasty may be due to turbulence from excessive widening of the vessel combined with the thrombogenic surface following endarterectomy. Until the significance of platelet accumulation is established platelet inhibitory therapy should be considered when patch closure is unavoidable.
EFFECT OF RABBIT THROMBOMODULIN ON THE INHIBITION OF THROMBIN BY ANTITHROMBIN IN PRESENCE OF EXOGENOUS HEPARIN: ROLE OF THE ACIDIC DOMAIN OF THROMBOMODULIN
Authors: Bourin M C , Bjôrk I , Boffa M C , Lindahl U 
Published: August 2018

Thrombomodulin (TM) is an endothelial cell membrane protein chat acts as a cofactor for Protein C (PC) activation by thrombin (T). Rabbit TM also prevents fibrinogen clotting by T (direct anticoagulant activity) and accelerates T inhibition by antithrombin (AT-dependent anticoagulant activity). Rabbit TM was previously found to contain an acidic domain (presumably a heparin-like polysaccharide), separated from the PC cofactor site but required for the direct and AT-dependent anticoagulant activities. Although binding of TM to T modifies the specificity of T, it does not involve a modification of the catalytic site or a global conformational change of the enzyme.A non-acidic form of rabbit TM was obtained by limited proteolytic degradation of the acidic form. The non-acidic form retained only the PC cofactor activity. The acidic and non-acidic forms of rabbit TM were compared with regard to their effects on the inhibition of T by AT in presence of exogenous heparin (hep). The AT-heparin complex was preformed by incubation for 5 min at 37°C of AT (0.1 μM) with high-affinity heparin (HA-hep, 250 ng/ml) and then added to a solution of T (90 nM) or T preincubated with either the non-acidic form (250 nM) or the acidic form (160 nM) of TM. Residual T activity was determined after various times for up to 5 min. Controls were performed by substituting buffer for TM. It was found that T bound to the non-acidic form of TM was inhibited at the same rate as free T (90% T inhibited within 30 sec), whereas T bound to the acidic form of TM was inhibited at a much slower rate (40 to 50% T inhibited after 5 min). Similar results were obtained even when HA-hep was used in excess (up to 750 ng/ml). The data suggest that the acidic domain of rabbit TM is primarily responsible for the retardation of T-AT complex formation in presence of exogenous hep. It is proposed that the polyanionic (endogenous heparin-like) component of rabbit TM blocks a site on T required for binding of T to hep in the ternary T-Hep-AT complex.
THROMBOMODULIN ON EXTRAVASCULAR MEMBRANES
Authors: Boffa M C , Burke B , Haudenschild C C 
Published: August 2018

The distribution of thrombomodulin (TM) antigen (Ag) was studied in the rabbit using an affinity-purified antibody raised against rabbit TM in a goat. Tissues were obtained from 8 New Zealand rabbits. Paraffin-embedded sections were prepared from various organs. Staining was performed using the avidin-biotin peroxi dase method. TM was found to be best and most consistently preserved after perfusion of the vasculature with fixative (buffered formalin) i.e. perfusion of the systemic vasculature via the ascending aorta and individual perfusion of the pulmonary, portal, coronary vasculature via the appropriate artery or vein. A positive reaction was observed on the entire endothelial surface of the vascular system: arteries, veins ahd capillaries. In contrast, parenchyma, secretory epithelia, connective tissue, cartilage, bone and nerve tissue were not stained.Interestingly, TM antigen was also found on the serosae: peritoneum, pericardium and epicardium and in the intralobular folds of the pleura, on the synovial membrane of the knee joint and on the entire surface of the spinal and cerebral arachnoid. The reaction was maximal on the intima of the large arteries, on the arachnoid and on the synovial membrane. The intensity of the reac tion did not depend on the organ examined but on the perfusion quality, except for arachnoidal and synovial membranes which were stained even without initial perfusion. The presence of TM on the membranes of body cavities was confirmed by the recovery of TM activity (as cofactor of protein C activation by thrombin in a chromogenic assay) in intraperitoneal lavage in vivo and in fluid used to rinse the brain arachnoidal surface ex vivo.These findings suggest the presence of potent anticoagulant mechanisms in the systems of slow circulating fluids such as the cerebrospinal and synovial fluids and in the virtual spaces of the serosae. While no thrombin is present there in physiological conditions, anticoagulant activity in these locations may be very important in case of even mild permeability changes, such as in inflammation. As anticoagulant systems assure the fluidity of blood in the vasculature, the TM(-PC) system on body cavities linings may assure free mobility and absence of adhesion of the membranes.
A LOW pH PREVENTS DENATURATION OF HEAT TREATED ANT I -HAEMOPHILIC CRYOPRECIPITATE
Authors: Skjonsberg O H , Gravem K , Kierulf P , Godal H C 
Published: August 2018

The AIDS epidemic has necessitated heat treatment of FVIII:C products in order to inactivate HIV-virus. When antihaemophilic cryoprecipitate (CP) is heated (68°C, 24 hours), the solubility and the concentration of FVIIIrC, von Willebrand factor and fibrinogen are substantially reduced. Such heat denaturation is prevented by addition of synthetic amino acids (SyntaminR 17) prior to lyophilization and heat treatment (Ref.rMargolis and Eisen, Skjønsberg et al.). The exact mechanism of this protective effect is not known, but in our opinion, the large buffering capacity of Syntamin is of major importance. Thus, in the presence of Syntamin (4 mg/unit FVIIIrC), a pH of 7.4 was maintained during lyophilization and heat treatment, while in ordinary CP, pH rose from 7.8 to 8.6 during the same procedure. Moreover, heat denaturation of CP was prevented by replacing Syntamin with a phosphate buffer, keeping a stable pH below 7.4. It is of interest to notice that apart from the effect on pH, we were unable to observe any influence of Syntamin on heat denaturation of plasma proteins in solution, on degradation of FVIII:C and fibrinogen by thrombin or plssmin or on the solubility of fibrin in plasma and CP.Heat treatment of CP at various pHs indicated that the :est product was obtained when pH .was kept between 6.5 and 6.3. By using an acidic buffer instead of Syntamin, the disadvantages of the latter, such as increased residual moisture leading tc discolouration, a probable stabilizing effect on virus and increased costs, may be avoided.
PATHOPHYSIOLOGY OF THROMBOCYTOPENIA AND RESULTANT CLINICAL INDICATIONS FOR PLATELET TRANSFUSION
Authors: Slichter Sherrill J 
Published: August 2018

Careful evaluation of platelet survival data in normal individuals and patients with thrombocytopeniasecondary to marrow aplasia has demonstrated that platelets are lost from circulation by two mechanisms a fixed fraction of platelets, amounting to approxi mately 7,100 platelets/ul/day, are lost randomly while the remaining platelets are removed by senescent mechanisms. At platelet counts of <100,000/ul, platelet survival becomes progressively shorter as the fixed platelet loss becomes a proportionately greater fraction of the circulating platelets. Thus, there is a direct relationship between platelet count and platelet survival in thrombocytopenic patients. Therefore, when judging the effectiveness of platelet therapy in thrombocytopenic patients, the influence of platelet count on platelet survival must be considered. As yet, there have been no studies to determine if there are ways to interrupt this fixed platelet loss? whether such therapy might improve platelet support in thrombocyotpenic patients by prolonging platelet survival? or, alternatively, whether such therapy might enhance the bleeding risk if random platelet removal is related to physiologic platelet-endothelial cell interactions.Besides taking into account the effect of thrombocytopenia on the expected response to platelet transfusions, the risk of alloimmunization with platelet transfusion therapy requires a careful assessment of the indications for platelet transfusions for each patient.Based on 51Cr-labeled stool blood loss measurements, we have determined that the bleeding risk is minimal at platelet counts above 10,000 platelets/ul.Only when the platelet count falls to a lower level of 5,000/ul is GI bleeding significantly increased. However, there are certain medications that may enhance the bleeding risk and require platelet transfusions to be given at higher platelet counts.In those patients who are thrombocytopenic, not because of failure of marrow platelet production, but rather because of accelerated platelet removal, indications for platelet transfusions must be adjusted to meet the particular problem. For example, for patients with autoimmune thrombocytopenic purpura, platelet transfusions are rarely indicated (one exception being intracerebral bleeding) because of the rapid rate of platelet removal and because the patients are usually releasing young hyperfunctional platelets from the bone marrow reducing the hemorrhagic risk at any given platelet count. In some patients with consumptive coagulopathies, even though platelet removal is rapid, platelets may have to be provided until specific therapy resolves the underlying disease process causing the platelet consumption. For these patients, increased levels of fibrinogen/fibrin degregation products, as well as various medications they maybe receiving, may produce platelet dysfunction necessitating platelet transfusions at higher platelet levels. Finally, massive transfusion patients may develop a dilution thrombocytopenia requiring platelet transfusions.
PLATELET TRANSFUSION THERAPY - FUTURE TRENDS AND FEASIBLE GOALS
Authors: Smit Sibinga C Th 
Published: August 2018

It is better to know than not to know the devil. Platelet transfusion therapy is one such devil. While the therapy initially is a benefit and might even be life-saving, it often implicates future problems which prohibit optimal efficacy.The factors determining both the beneficial and the prohibitive effects are complex and not seldom masked. Problem areas include the logistics of availability, the prevention of immunological effects and incompatibilities, the prevention of trans- missable diseases and the prediction of clinical efficacy.Efforts for optimising platelet transfusion therapy should focus on safety, purity, potency and clinical efficacy. However, each of these premises has to be outlined with precision in order to allow targetted development.Major areas of attention will be the selection and utilisation of available resources, the options for purification, efforts to optimise processing, preservation and storage conditions, innovation of the in vitro viability concept and alternative approaches to selection in order to increase the predictive value of compatibility testing.
SPORADISM INVESTIGATION AND CARRIER DETECTION IN HAEMOPHILIA A BY RFLP ANALYSIS
Authors: Bernardi F , Marchetti G , Vannini F , Felloni L , Panicucci F , Conconi F 
Published: August 2018

Restriction fragment lenght polymorphisms (RFLPs)analysis has been employed for carrier detection andfor sporadism study in Haemophilia A. Three RFLPs, one intragenic in FC8 (647/BcII) and two with close linkage to Haemophilia A at DXS52 (Stl4/Taql) and DXS15 (DX13/BgIII), were used.In 20 families 29 carrier status determinations havebeen performed.In order to investigate sporadicity and to estimate the sex ratio of mutation rates directely, 17 families with isolated cases of haemophilia A were studied.In eight out of the 17 families the RFLPsanalysis excluded the carrier status of the maternalgrandmothers.Since by hemostatic studies the eight mothers of the propositi were shown to be haemophilia carriers, the origin of the newly mutated genes was inferred from the RFLP patterns: six haemophilic genes derive from the normal maternal grandfathers and two from the maternal grandmothers.Possible recombinations between FVIII locus and the extragenic RFLPs loci have to be considered; however the intragenic Bell RFLP is informative in five out of the eight families and the DXl3 and Stl4 patterns are concordant.The data indicate a higher mutation rate in males than in females gametes as previously suggested, althought not unanimously, by segregation analysis and coagulation studies. The RFLP analysis in a large number of families with isolated cases of haemophilia isnecessary to define the precise ratio of sex mutation rate for this disease.Work supported by P.F. Ing. Gen. Basi Mol. Mai. Ered. Contratto CNR N 8400877.
NEW CHROMOGENIC SUBSTRATES FOR THE DETERMINATION OF COAGULATION AND FIBRINOLYSIS ENZYMES
Authors: Stüber W , Schiwek D , Becker U , Heimburger N 
Published: August 2018

A new type of chromogenic substraces based on derivatives of phenoxazine is presented. Particularly interesting is the blue dye 7-amino-3-diethylamino-8-methylphenoxazine (ADMP) with a molar extinktion coefficient of about 80,000 at 624 nm. Peptides were linked to the aminogroup of the dye and red coloured substrates were obtained with a λmax value of about 540 nm. On account of the distinct difference of the λmax values and the negligable influence of the absorption peaks of the acylated and the free dye this chromophore is suitable for the synchesis of substrates. Besides the spectral properties of chese new chromogenic peptides we determined their characce-riscics using serine proteases involved in the process of coagu-lacion and fibrinolysis. In comparison co para-nitroaniline substrates the introduction of the relatively bulky ADMP into the peptide sequence led to products with superior properties in respect of sensitivity and specificity.It was found that the ADMP substrates are particularly favourable for the determination of thrombin, urokinase and activated protein C in the presence of other proteases.
CONTINUOUS PERIOPERATIVE ADMINISTRATION OF Cl-ESTERASE-INHIBITOR CONCENTRATE AND APROTININ IN CARDIOVASCULAR SURGERY
Authors: Poppv S , Philapitsch A , Murday H , Fenyes J , Kirchhoff P G 
Published: August 2018

The results obtained in our randomised study in 3 groups of patients performed in 1982/83 suggested the administration of protease inhibitors to be effective in counteracting the activation of the kallikrein, coagulation and fibrinolytic systems during extracorporeal circulation (ECC) thus lowering the rate of postoperative bleeding complications. Since Cl-esterase-inhibitor (Cl-INH) proved to be the main inhibitor of the kallikrein (KK) system and aprotinin that of plasmin further studies to investigate the efficacy of a combined treatment and to develop an improved dosage regimen were initiated in 1985.Pilot:1: 3 patients/aprotinin; pilot 2: 3 patients/Cl-INH Concentrate; pilot 3: 5 patients/Cl-INH Concentrate + aprotinin. Test parameters included: protein/Biuret; Cl-INH/rocket immune electrophoresis and chromogenic substrate method; kaolin induced kallikrein generation; plasminogen activation using streptokinase; plasmin inhibiton capacity; coagulation factors I, II, V, VII, VIII, and X; reptilase clotting time, thrombin time; platelets and the thrombelastogram.15 blood samples were taken at regular intervals over approx. 16 hours before, during and after surgery, as well as on the first and second postoperative day.Dosage in pilot 1 and 2 was 500 × 103 KIU aprotinin and 1500 PU Cl-INH, respectively, followed by the continous i.v. infusion of 125 × 103 KIU aprotinin/h and 125 PU CI-INH/h, respectively over approx. 16 hours. This regimen still appeared inadequate to prevent the activation of the KK and fibrinolytic system. In pilot 3 therefore, the continous infusion of both concentrates was increased by 100 % (250 × 103 KIU aprotinin/h + 250 PU Cl-INH/h), while the bolus-injection remained the same as in pilot 1 and 2. Using this optimised combined regimen parameters of the kallikrein, coagulation and fibrinolytic system remained almost unchanged compared to values obtained prior to ECC.
ORNITHO-KININOGEN: ITS ISOLATION AND CHARACTERIZATION
Authors: Kimura M , Sueyoshi T , Morita T , Tanaka K , Iwanaga S 
Published: August 2018

In mammals, three kinds of kininogens, high-Mr kininogen, low-Mr kininogen and T-kininogen, are known and their structures and functions have been well studied. However, little is known about non-mammalian kininogens and their existence has been known only by the release of plasma kinins. In 1966, Werle et al. reported that an ornitho-kinin liberated by tissue kallikrein from chicken, plasma differs;from mammalian kinins in its amino acid composition. Since that, there is no report about the structure of ornitho-kinin.In this study, ornitho-kininogen was isolated from chicken plasma by two steps with S-alkylated papain affinity and DEAE-5PW columns. The yield was 1.7 mg from 44 ml of plasma. The purified material gave a single band on SDS-PAGE with or without 2-mercaptoethanoL and on disc-PAGE, and the molecular weight was estimated to be 74,000 on SDS-PAGE by Ferguson plot. Ornitho-kininogen seemed to belong to mammalian high-Mr kininogen, based on the amino acid composition, and the molecular weight, and no kininogen corresponding to low-Mr kininogen and T kininogen was found in chicken plasma. In fact, ornitho-kininogen was degraded rapidly by bovine plasma kallikrein, liberating an ornitho-kinin, and the resulting kinin was separated by reversed phase HPLC on a column of Cosmosil 5C18-P. The amino acid sequence of ornitho-kinin was established to be Arg-Pro-Pro-Gly-Phe-Thr-Pro-Leu-Arg, in which the composition was different from that reported earlier by Werle et al. This sequence was similar to that of bradykinin but the two substitutions of Thr-6 and Leu-8 for Ser and Phe were found. Ornitho-kinin induced a hypotension on chicken and contracted the isolated smooth muscle. However, it did not any effect on the isolated rat uterus, suggesting that the specificity may be due to replacement of Phe-8 by Leu. The NH2-terminal 30 amino acid residues of ornitho-kininogen exhibited 43 % identity with that of bovine kininogen.