bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thrombin And Factor Xa Inhibition By Hog Mucosal Heparins Fractionated According To Charge Density
Authors: Poon M-C , Hurst R E 
Published: July 2018

Since heparin inhibition of thrombin (ThI) and factor Xa (XaI) have been shown to depend differently upon the molecular size of heparin, this study was undertaken to determine their dependence upon charge density (Z). Fractions varying systematically in charge density were isolated from 3 hog mucosal heparin preparations (2 decolorized and 1 undecolorized) using a 2 phase sequential extraction system. Xal assay was performed by the plasma clotting method of Yin using a commercial kit. ThI assay involved inhibition of plasma clotting by partially purified bovine thrombin.When heparin potencies were plotted against Z2, all 3 preparations determined by both assays showed a linear relationship with the exception of one fraction with the highest charge density. For each of the 2 assays, the curves for the 2 decolorized preparations were essentially parallel. Although the initial slope of the undecolorized preparation was parallel to those of the decolorized heparins for each assay, the potency of the fraction with highest charge density was different. Thus, all 3 preparations appeared similar for a given anticoagulant function except for the highest charged fractions. When the activity of each preparation was compared to each other, the XaI and ThI curves did not necessarily parallel each other or to the APPT potency curve. No clear cut systematic relationship or differential effects could be established between the heparin anticoagulant functions in relationship to charge density differences. The data suggested also heterogeneity of activities within each fraction with apparent charge density homogeneity.
Effect Of Some Experimental Conditions On The Activity Of A Low Molecular Weight (LMW) Heparin Fraction Compared To A Hight Molecular Weight (HMW) Fraction
Authors: Aiach M , Nussas C , Mardiguian J 
Published: July 2018

In this work, we aimed to demonstrate that different methods can give different results when the same pair of heparin samples are compared, even when specific antiprotease assays are performed. For this purpose, the effect of heparin on factor Xa (Xa) or thrombin (IIa) inhibition by antithrombin III (AT III) was examined in the presence of varying amounts of AT III, during different incubation times.The molecular weight of the two heparins were 5,200 (LMW) and 42,000 (HMW). Solutions containing 2 y.g per ml of heparin and a 1.4 to 15 μM freshly purified human AT III were incubated with either bovine Xa or human Ila. After a 20, 30, 60 or 90 secondes incubation at 30° C, the remaining protease activity was measured by the initial velocity of a chromogenic substrate. The method was entirely automated using a reaction rate analyser and an adapted program.The antiprotease activity of the LMW heparin (related to the HMW heparin activity) varied from 0.23 to 0.89 in the anti Xa system, from 0.30 to 0.77 in the anti Ila system. The ratio of LMW to HMW activity was a parabolic function of either AT III concentration or incubation time. No meaning differences were observed between anti Xa and anti Ila activity when the inhibiting capacity was assayed in the same experimental conditions. These results suggest that the relative activities of HMW and LMW fractions depend upon the assay procedure. AT III concentration as well as incubation time are of particular importance.
Fibrinogen And Hematocrit In Viscosity Measurements
Authors: Grotta J , Bigelow R , Olson J , Haynie D 
Published: July 2018

We have studied the relative contribution of fibrinogen and hematocrit to viscosity preparatory to therapeutic reduction of viscosity in a rat model of cerebral ischemia.Assuming Newtonian flow characteristics, we first devised a model of the interaction of these variables. Estimating the relative volume of RBCs, plasma, and visco-active proteins suspended in the plasma, assuming random collision of these components, and assuming.that viscosity is dependent only on RBCs and vaso-active proteins, we have derived the following relationship: viscosity α K1(Hct+.l)2 +K2. We then performed a linear model analysis of measured viscosity (range 1.5-12.3 cp) vs measured fibrinogen (range 0-270 mg%) and hematocrit (range 0-.45) in rat blood which was composed of either normal whole blood or mixtures of washed RBCs, defibrinogenated plasma, and known quantities of fibrinogen. Viscosity was measured in a Wells-Brookfield cone-plate micrcjjviscometer at shear rates ranging from 22.5 sec to -450 sec .Hematocrit had a significant effect on viscosity at all shear rates measured, though this effect was greater at lower shear rates. Fibrinogen^had no effect on viscosity at shear rates above 22.5 sec-1.These relationships are consistent with previously published data demonstrating an effect of normal concentrations of fibrinogen on viscosity only at shear rates below those accurately measured by our viscometer (i.e., less than 11 sec-1 ). We did not study fibrinogen concentrations over 300 mg%. Furthermore, there did not appear to be an interaction between fibrinogen and Hct, indicating that the absence of fibrinogen at shear rates measured in this study did not affect the properties of RBCs as they pertain to viscosity.The accuracy of our model enables us to correct for varying Hct from animal to animal as long as measurements are performed in the Newtonian range. Presently we are testing a model of Hct and fibrinogen vs viscosity applicable to shear rates at which blood becomes non-Newtonian.
Self-Assembly Of Fibrin Monomers Measured By Quasielastic Light-Scattering
Authors: Guinnup D E , Schultz J S 
Published: July 2018

Purified fibrin monomer solutions were prepared in 1 M sodium bromide by alternation of precipitation and solubilization with pH adjustments between 6.0 and 5.3. The final preparation, at pH 5.3, was checked for monodispersity and purity by quasielastic laser light-scattering and was found to have a translational diffusion coefficient of 2.14 × 10-7 cm2/sec and a radius of gyration of 286 A, in excellent agreement with published data.The kinetics of fibrin self-assembly was monitored in-situ by measuring the autocorrelation function and mean intensity of scattered light with time after abruptly changing the pH froft 5.0 to 6.3 in 1 M NaBr. The data were most consistent with an assembly model wherein fibrin associated with itself in an overlapping staggered end to end configuration. The evolving particle size distribution of fibrin fibrils was obtained by deconvoluting the autocorrelation functions obtained over a 30 minute period and unexpectedly revealed that larger aggregates, containing greater than about 6 fibrin units, were greatly favored over smaller aggregates, dimers, trimers, etc. Also, while the rate of fibrin assembly appeared to be proportional to the square of the monomer concentration, consistent with simple aggregation theory, the probability of a collision between particles resulting in the growth of a fibril was very small.Additional in-situ experiments under laminar shear conditions in the physiological range showed the same pattern of fibril size distribution, except that the rate of self-assembly decreased about 30% as shear increased to 1000 sec-1.
Gel Structure And Clotting Time
Authors: Blombäck B , Okada M 
Published: July 2018

Ferry and Morrisson found on the basis of the mechanical and optical properties of fibrin gels that they ranged between two extreme types: fine or transparent and coarse or opaque. We have now developed a device permitting studies of flow properties of gels. The gels are formed in standardized cups (1.47×2.5 cm) which are fitted into a special holder attached to a reservoir for application of buffer solution for the flow measurement. Gels were formed by mixing thrombin or Batroxobin with fibrinogen solutions of different protein concentrations (1-4 g/1), pH (6.5-8.2) and ionic strengths (0.1-0.23). All these studies were in addition performed at different enzyme concentrations. The gels were left in the cups for complete gelation to occur (1-2 hours) and subsequently the same buffer as used for gel formation was percolated through the gels at room temperature and a constant pressure gradient. In parallell experiments the formation and optical properties of the gels formed was studied by turbidity measurement at 450 nm. After a lagtime rapid increase in turbidity occurred. The lag-time was defined as the “clotting-time”.We found that for both enzymes the flow is related to the optical properties of the gels, being fast for the opaque and slow for transparent gels. Fast flow is thus favoured by low pH and low ionic strength. The flow rate is furthermore inversely related to the gel concentration. Of particular importance was the finding that under all conditions so far studied there was, within a wide range, a direct relationship between clotting time and flow rate. This suggests that the final structure of the gels is determined by events preceeding the gel formation. These events are enzymatic activation and alignement of activated molecules. Gel formation is therefore very likely an ordered process resembling that of crystallization. Batroxobin and thrombin gels having the same clotting times displayed different flow properties suggesting that different types of polymers are formed on release of one (FPA) and two (FPA + FPB) activation peptides, respectively.
Fibrinogen, Factor XIII And Antiplasmin In Hemostasis
Authors: Amburs C M , Ambrus J L , DeRisi D , Petrelli N J , Cohen H 
Published: July 2018

Removal of large numbers of pulmonary metastases in cancer patients represents a serious problem since adequate hemostasis requires meticulous suturing and prolonged open chest procedures. For this reason, we tried to develop methods for obtaining rapid hemostasis. A double syringe system was constructed in which simultaneously we discharged from one syringe a mixture of highly concentrated human fibrinogen, platelet growth factor, antiplasmin, and Factor XIII (FS); from the second syringe we discharged thrombin and calcium chloride. After a few mm of passage through the common part of the nozzle, the mixture coated the area of pulmonary resection. In a series of experiments in dogs and stumptailed monkeys (Macaca arctoides) bleeding times of comparable pulmonary biopsies were recorded. FS alone or in association with suturing produced rapid hemostasis and as shown by follow-up histopathologic examination promoted healing without significant tissue reactions. This method proved to be superior in comparative experiments to the use of cryoprecipitate and thrombin or microfibrillar collagen preparations.In a series of experiments, splenic injuries were induced in dogs, normally requiring splenectomy. The same three hemostatic methods described above were studied in this model. Adequate hemostasis was obtained with FS. This material appeared to be suitable to obviate the need of splenectomy and its hematologic consequences in traumatic rupture of the spleen.
Congenital Deficiency Of Cyclo-Oxygenase In A Woman With Generalized Arteriosclerosis
Authors: Boda Z , Tamás E , Altorjay L , Pflieger Gy , Rak K 
Published: July 2018

A 52-year old woman with congenital cyclooxygenase deficiency who had moderate bleeding tendency and severe generalized arteriosclerosis is reported.Diagnosis based on the following data: secondary platelet aggregation induced by adrenaline, ADP, ristomycin, collagen, thrombin was absent; platelet completely failed to aggregate by arachidonic acid while aggregation induced by calcium ionophore A23187 was normal; no malondialdehyde formation could be detected in the platelet rich plasma /PRP/ in four different times /for exclu- sing any drug effects/. The abnormal adrenaline and ADP induced aggregation were not corrected when patient’s PRP was mixed in equal proportions with that of a normal subject ingesting aspirin.Although our patient had been free from severe thrombotic episodes, expressed signs of generalized arteriosclerosis could be detected.Until now only five cases of congenital deficiency of cyclo-oxygenase have been described /Malmsten et al., Weiss and Lages, Lagarde et al., Pareti et al./. However, in these patients no signs of arterial vascular diseases were mentioned.The special importance of this new case comes from the fact that life-long deficiency of cyclooxygenase enzyme could not protect from progressive vascular disease which might prove again that chronic intake of large doses of aspirin cannot prevent arterial disorder.
Suppressive Effect Of Neoratal Thymectomy On Occlusive Arterial Thrombosis In Sensitized Rats
Authors: Uzunova A 
Published: July 2018

It has been found that lymphokines can induce thrombocyte aggregation and biood coagulation.The present study investigated the development of occlusive arterial thrombosis (OAT) in both male and female Wistar rats with altered immunologic background in order to elucidate the immunologic mechanisms in the pathogenesis of OAT.At the age of 10 weeks neonatally thymectomized rats and sham operated litter mate controls were sensitized with 500g of bovine serum albumin (BSA), injected with complete Freund’s adjuvant in a single hind footpad and a second control sham operated rats were injected only with saline. All animals were skin-tested with 30^g of BSA in saline at 7 and 14 days. Arthus reactions were read 3 to 4 hr. Both the average diameter in millimeters and thickness were recorded. Only reactions eaual and greater than 7 mm in diameter were regarded as positive.Experimental OAT was induced when rats reached 3 months of age using a polyethylene loop inserted in the abdominal aorta. The mortality rate (MR), dry thrombus weigt (TW) and loop obstruction time (OT) served as criteria for asessment of thrombosis. According to all the criteria used there was a statistical!v significant sun- nression of the development of occlusive arterial thrombosis in the the neonatally tbvmectomized rats of either sex. The oreviouslv observed sex diferense in OAT was more pronounced.The data presented suggested an involvement of immunologic mechanisms in the thrombogenesis in the arteries and that suitable inhibitors of the immune responses could prove to be of therapeutic value.
Influence Of High Molecular Weight Factor VIII On The Expression Of Factor VIII Procoagulant Activity
Authors: Muntean W , Hathaway W E , Montgomery R R 
Published: July 2018

The relationship of the high molecular weight (HMW) moiety and low molecular weight (LMW) moiety of factor VIII in expressing procoagulant activity (VIII C) was studied. LMW VIII C was prepared by immunoadsorbent chromatography; HMW VIII was prepared by chromatographing hemophilic cryo- precipitate in 4% agarose. The LMW VIII C obtained by immunoadsorbent chromatography gave higher VIII C values when tested in the one stage partial thromboplastin time (PTT) system using von Willebrand’s disease plasma as substrate than using hemophilic plasma as substrate. This finding was shown to be due to the VIII related antigen (VIIIR:Ag) in the substrate plasmas. When the VIIIR:Ag was removed from the hemophilic substrate plasma by immuno-adsorption, the VIII C values obtained for the LMW VIII C were higher. Also, adding purified HMW VIII to the von Willebrand’s disease substrate plasma resulted in lower VIII C values for the LMW VIII C in the PTT system.When the LMW VIII C was tested in the two stage assay, all VIII C was adsorbed to A1(0H)3. The adsorption of the LMW VIII C was prevented by mixing it with hemophilic plasma. From normal undiluted plasma only 5-21% of VIII C and no VIII related antigen were adsorbed to A1(OH)3, but after activation of the factor VIII of normal plasma by small amounts of thrombin, most of the VIII C was adsorbed. No VIII related antigen was adsorbed after activation.Nevertheless, when unadsorbed LMW VIII C was assayed by the two stage method both with and without HMW VIII or VIIIR:Ag, the results were the same.Our studies suggest that VIIIR:Ag prevents to some extent the activation of LMW VIII C. LMW VIII C that is not bound or protected by VIIIRiAg is adsorbed from plasma by A1(0H)3. These findings may help explain the differences for VIII C found in some patients and certain clinical circumstances with the one and two stage assays.
Comparison Of Naturally Occurring And CaCl2-Separated Canine Factor VIII-Coagulants Free Of FACTOR VIII-Related Antigen
Authors: Benson R E , Dodds W J 
Published: July 2018

Previous studies demonstrated that plasma from dogs homozygous for von Willebrand’s disease (VWD) without detectable factor VUI-related antigen (VIII:RAg) contained moderate levels of a stable factor VIH-coagulant (VIII:C), which had lower apparent molecular weight and combined with the VIII:RAg of canine hemophilic plasma. We have now compared this VWD-VIII:C to the CaCl2-separated form of VIII:C prepared from normal canine factor VIII. The VWD plasma was fractionated at room temperature by 6% agarose gel filtration in 0.15M NaCl and 0.24M CaCl2 buffers, pH 7.25; the VIII:C eluted in each buffer with a relative elution volume (Ve/Vo) of 1.4. Isolated lower molecular weight VIII:C stabilized with albumin (5 mg/ml) and dialysed free of Ca++ was prepared from normal purified canine factor VIII by elution in 0.24M CaCl2 buffer. This CaCl2~separated VIII:C was rechromatographed in both buffers as above and had a Ve/Vo of 1.9. When the VWD and CaCl2 forms of VIII:C were each combined with canine hemophilic plasma and gel filtered in 0.15M NaCl buffer, the VIII:C’s now appeared at the void volume. These mixtures with 1/10 volume 2.4M CaCl2 added before or after combination were also analyzed in 0.24M CaCl2 buffer. The CaCl2-VIII:C eluted with a Ve/Vo of 1.9 regardless of the order of 2.4M CaCl2 addition, but the VWD-VIII:C eluted with Ve/Vo’s of 1.4 when CaCl2 was added before mixing and 1.9 when added afterwards.Thus, when mixed with hemophilic plasmas both the CaCl2 and VWD forms of VIII:C exhibited similar combination and separation characteristics. However, the finding that the CaCl2-VIII:C is of apparent lower molecular weight than the VWD form suggests that the CaCl2-separated VIII:C is different from the naturally occurring form of VWD (VIII: RAg-free) VIII:C.
Factor VIII/Von Willebrand Factor Protein Sensitivity Of Periodic Acid Schiff Stain To Carbohydrate Deficiency
Authors: Gralnick H , Jackson G , Williams S , Cregger E 
Published: July 2018

Carbohydrate (C) deficiency of the factor VUI/von Willebrand factor (f. VIII/vWf) protein has been implicated as one of the molecular defects of von Willebrand’s disease. The periodic acid Schiff (PAS) reaction in polyacrylamide gel electrophoresis (PAGE) has been used as a screening test for C deficiency. To ascertain the sensitivity of this reaction to the C content of the f. VIII/vWf protein we have purified the normal protein and compared the Coomassie to PAS staining reaction of the subunit of the intact, asialo (neuraminidase-treated), asialo-agalacto (neuraminidase and β-galactosidase-treated) derivatives and a fourth derivative which was treated with a mixed glycosidase which included neuraminidase, β-galactosidase and N-acetyl-glucosaminidase. Gels were run simultaneously, one stained with Coomassie blue and the other with PAS and at various time intervals after staining the gels were scanned.Studies of the intact f. VIII/vWf protein revealed that the PAS and Coomassie stains could be compared from 24 hours up to 7 days with no significant changes. The desialated f. VIII/vWf protein had insignificant differences in the PAS stain compared to normal (range 81-108% of intact). However, the asialo-agalacto derivative (36% of intact) and the f. VIII/vWf treated with the mixed glycosidase (24% of intact) had significantly reduced PAS staining in relation to normal. C analysis of the different f. VIII/vWf proteins revealed that removal of the sialic acid reduced the C 30% while in the asialo-agalacto the C was reduced 47% and in the mixed glycosidase-treated material the C was reduced 78%. The PAS stain is not very sensitive to the sialic acid content of the f. VIII/vWf protein and reduction of 30% of the C does not affect the PAS stain. Since the PAS stain is relatively insensitive to significant carbohydrate deficiencies of the f. VIII/vWf protein, the use of the PAS stain in PAGE may not be an adequate test to ascertain C content of the f. VIII/vWf protein.
A family with factor XII deficiency: a family study suggesting that factor XII levels are determined by the presence of 3 codominant alleles with variable penetrance
Authors: Roberts D , Hayne O , Fraser E 
Published: July 2018

We studied 15 members, in 3 generations of a family in whom the propositus had complete factor XII deficiency. The parents had factor XII levels of 59% and 62%. Three of the siblings had factor XII levels of less than 1%. Three more had factor XII levels of (30±5%). In 3 the levels ranged from (60-87%) and the remaining 2 siblings had levels exceeding 100%. The propositus with a level of less than 1% gave rise to an offspring with a level of 48%.We propose that the gene controlling factor XII production consists of 3 separate alleles expressed codominantly: A - normal, B - low, O - absent. Members of the family with 100% factor XII activity have genotype AA; those with less than 1% activity have genotype OO; subjects with levels of 30% have genotype BO, and those with levels of 60% have genotype AO. We feel our study sheds new light on the inheritance of factor XII and the wide variation of levels in the general population.
In Vivo Thromboscintigraphy With Indium-111-Labeled Platelets In A Dog-Catheter Model
Authors: Price D C , Lipton M J , Hartmeyer J A , Prager R J 
Published: July 2018

Autologous platelets from mongrel dogs have been labeled with 200-400 μCi Indium-111 complexed to oxine using the technique of Thakur, McAfee and others. Intraarterial thrombogenesis was studied in vivo by advancing a polyethylene angiographic catheter from a femoral into a carotid artery, then serially imaging the catheter over periods of 0.5-3 hours by scintillation camera with interfaced computer. Quantitative uptake was derived from computer processing of the studies, and compared with in vitro In-111 counts and clot weight obtained at various times by catheter excision. Labeled platelets were injected prior to or at periods of 2 or 24 hours after catheter insertion in order to evaluate both forming and preformed thrombus. Platelet In-111 radioactivity was found to peak at 30-80 minutes in newly forming thrombus and to fall thereafter. In vitro In-111 activity correlated well with wet clot weight.In-111 (% inj. dose) = 0.00209 × (mgm clot) + 0.00091 (r = 0.882) (n = 24)In vivo correlation was also linear, but with a broader scatter of data points. At the peak, In-111 uptake was 0.06044). 019% of i.d. per cm of catheter by in vitro measurement, and clot weight was 27.9±5.6 mgm per cm. Preformed thrombus picked up substantially less of the label (2 hr: 0.017±0.011% i.d./cm; 24 hr: 0.00245).001% i.d./cm) (n=6) and was not imageable in vivo. The study documents the effectiveness of this new platelet radiolabel for quantitative in vivo scintigraphy of newly forming thrombus, which can be useful for comparison of different anti-thrombogenic regimens and different biomaterials. It also indicates, however, the problems that can be anticipated in attempting to image established thrombus in vivo.