bluuebunny/crossref_metadata_2025_split huggingface dataset:
SEVERELY IMPAIRED SYNTHESIS OF PLATELET ACTIVATING FACTOR IN CHONDRO DYSPLASIA PUNCTATA RHIZOMELIA PATIENTS
Authors: Sturk A , Schaap M C L , Prins Heymans A , ten Cate J W , Wanders R J A , Heymans H S A , Schutgens R B H , van den Bosch H 
Published: August 2018

The first steps of the de novo synthesis of alkoxyether lipids, like plasmalogens and platelet activating factor (PAF) are localized in the peroxisome. We have previously reported the severely impaired PAF synthesis in Zellweger patients. These patients lack cytochemically detectable peroxisomes, and have a severely impaired alkoxyether lipid synthesis. However, chondro dysplasia punctata (CDP) patients have also been shown to have an impaired alkoxyether lipid synthesis. We therefore investigated PAF synthesis in CDP patients.Platelets and leucocytes were isolated from 3 CDP patients. Leucocytes from normal controls produced 4678 ± 2033 pMoles PAF/10 cells (n=6, range 1698-7058) when optimally stimulated with Ca2+-ionophore A23187. Normal control platelets produced 0.6 ± 0.3 pMoles PAF/10 cells (n=6, range 0.3-1.0) when optimally stimulated with thrombin. PAF synthesis by the leucocytes of the patients was severely reduced, but detectable. Leucocytes from patient 1, 2 and 3 synthesized 9, 660 and 325 pMoles PAF/10 cells respectively. Platelets from the patients 1, 2 and 3 synthesized 0.1, 0.2 and 0.2 pMoles PAF/10 cells respectively.Platelet aggregation, induced by ADP, PAF, or thrombin (also in the presence of inhibitors of the first and second pathway of platelet activation) was normal.We conclude that PAF synthesis is severely impaired in leucocytes and reduced in platelets from CDP patients. The residual platelet PAF synthesis may suffice to warrant normal platelet functioning.
SEPARATION OF FIBRINOGEN FRAGMENTS ON GLYPRQARGPROLYS-FRACTOGEL
Authors: Kuyas C , Haeberli A , Straub P W 
Published: August 2018

The tetrapeptide GlyProArgPro, which corresponds to the newly exposed N-terminal sequence of fibrin a-polypeptide chain after the action of thraribin, has a binding site in the C-terminal part of the ;-chain as suggested by several authors. Using Gly-ProArgProLys-Fractogel (GPRPK) chrcmatography we tried to isolate a fibrinogen fragment, obtained with different enzymes and conditions, which includes the binding site for GPRP. Human fibrinogen was digested by plasmin in presence and absence of Ca-ions, and the resulting lysates were applied in 0.05 M triethanolamine (TEA), 0.1 M NaCl pH 7.4 to the GPRPK-Fractogel. The gel was washed extensively with TEA-buffer and the adsorbed protein was eluted with 6M urea in TEA-buffer. The protein containing fractions were analyzed iiununologically with anti-fragment E- and with anti-fragment D antibodies. Human fibrinogen was also digested with endopeptidase Arg-C in O.IM NaHco3 pH 8.0 at 37C over night. The enzyme cleaves fibrinogen to fragments, one of which comprising the y-chain sequence 275-375 which is said to contain the fibrin polymerization site. The Arg C-lysate was chromatographed on GPRPK-Fractogel. All fragments were analyzed by SDS-electrophoresis and by reversed-phase HPLC.Fragment D1 was the only fibrinogen fragment which was adsorbed on GPRPK-Fractogel. All other assayed fibrinogen fragments obtained by enzymatic cleavage, showed no affinity to GPRPK-Fractogel. These results demonstrate that for the binding of GPRP to fibrinogen a conformationally intact γ-chain remnant of the fragment D is required.One step chrcmatography using GPRPK-Fractogel can thus also be used to isolate fragment D1 in high purity fran plasmin lysates of fibrinogen.
DISCREPANCIES BETWEEN VENOGRAPHY AND REAL TIME B MODE ULTRASOUND IMAGING IN THE DIAGNOSIS OF DEEP VEIN THROMBOSIS
Authors: Elias A , Le Corff G , Bouvier J L , Villain Ph , Serradimigni A 
Published: August 2018

Methods : in this prospective study, real time B Mode ultrasound imaging (USI) was compared to bilateral ascending contrast venography, double blindly, in 430 patients suspected of deep vein thrombosis (DVT) or pulmonary embolism.A complete scan of the venous system from the inferior vena cava to the calf veins, was performed with a high resolution duplex system (DIASONICS DRF 400) and coupled systematically with a C.W. Doppler examination. The results obtained by USI were thus compared to the venograms performed on a total of 854 legs.Results : there are corresponding results in 95% of the legs (808/854). If we consider venography as the standard of reference, the sensitivity of USI is 98% (325/333) and the specificity 94% (483/514). Isolated calf vein thrombosis are detected in 91% (84/92) of the legs and proximal DVT in 100% (241/241) in this series whatever the topography and the extension of the thrombosis and whatever the degree of the obstruction of the vein.Discrepancies found in 46 legs are related to :- 8 DVT located in the calf (6 in the presumed healthy leg) diagnosed only by venography.- 27 DVT (18 distal, 9 femoral or iliac) detected only by USI- 9 doubtful examinations with USI not confirmed by venography- 2 doubtful venograms with negative USI test.Comments : Calf vein thrombosis especially located in the soleal sinuses and the gastrocnemius with in most cases the direct image of the thrombus are more often detected by USI provided that the technique and the equipment are appropriate.The absence of visualisation of venous segments with venography is not specific of venous thrombosis. These veins non affected by the thrombosis are not filled by the contrast medium when located above in occluded ilio-femoral or ilio-caval junction or when they are the site of extrinsic compression. The direct image of the vein and the surrounding structures obtained with USI enhances the diagnostic sensitivity and specificity and provides precision of the exact extension of the thrombosis.Due to these differences, can venography still be considered as the standard of reference in the diagnosis of DVT and their precise localisation ?
FIBRIN ACTIVATABLE UROKINASE (FA-UK): A LATENT FORM OF UK IN URINE RELATED TO A COMPLEX WITH AN INHIBITOR/FIBRIN-BINDING CO-FACTOR OF UK AND POSSIBLY OF PRO-UK
Authors: Dwivedi C , Pannell R , Gurewich V 
Published: August 2018

The plasminogen activator activity in urine, expressed in IU, was found to be consistently 2-3 fold higher by fibrin plate assay than against amidolytic substrate (S-2444). Moreover, when the S-2444 assay was preceded by incubation of urine with soluble fibrin, a similar 2-3 fold increase in activity was found. The fibrin effect was dose-dependent and specific for various forms of soluble fibrin but not fibrinogen. The fibrin activatable activity was inhibited by antibodies to UK and was termed FA-UK. About 1/3 of the total UK activity in freshly voided urine was composed of FA-UK. The relative FA-UK content of urine was found to be enhanced by concentration. The FA-UK bound to fibrin/Celite. By gel filtration (S-200) of urine or by zymography, the MW of FA-UK was - 100K. Pretreatment of the samples with soluble fibrin prior to SDS-PAGE enhanced the amount but not the position of the FA-UK activity on the zymogram, indicating that the complex was not dissociated by fibrin. Pretreatment with hydroxylamine (1M) eradicated the FA-UK activity in urine. Addition of UK or pro-UK to urine followed by concentration (X10), increased the 100K band on the zymogram. Under conditions of this experiment, it was shown that little conversion of pro-UK to UK occurred suggesting that complexation occurs with pro-UK as well as with UK. Moreover, a - 100K FA-UK band on zymography was demonstrated afer addition of pro-UK to urine treated with DFP (5mM) or GGAck (20juM) to inactivate UK.It was concluded that a - 50K inhibitor in urine, with properties similar to an inhibitor described by Stump et al (JBC 261:12759, 86), acts as a co-factor for fibrin binding of UK and possibly also of pro-UK. It is speculated that this co-factor may contribute to the fibrin-specificity of pro-UK by localizing both it and its activated derivative, UK, to the fibrin surface.
AMINO ACID SEQUENCE OF THE THROMBIN-BINDING SITE ON PLATELET GLYCOPROTEIN Ib
Authors: Yamamoto K , Kawasaki H , Suzuki K , Tanoue K , Kosaki G , Yamazaki H 
Published: August 2018

Amino acid sequence of the thrombin-binding site on platelet glycoprotein (GP) Ib was determined and the effects of the synthesized analogous peptides on thrombin-induced aggregation were studied. Crude platelet membrane fraction solubilized with 5mM dithiothreitol and 0.2% Tween 20 was applied to a WGA-Sepharose. The bound fractions were eluted with 0.3M N-actylglucosamine, then applied to a TM60 ( a monoclonal antibody against GP Ib)-Affi-gel column. Only one GP was bound to the column and was eluted with 50mM glycine-HCl, pH3.0, containing 0.2% Tween 20. SDS-PAGE showed a single band of 130kDa, corresponding to GP Ib alpha chain (GP Ibα). When the purified GP Ibα was digested with trypsin, two fragments (94kDa . and 43kDa) were obtained. The 43kDa fragment was shown to bind to both affinity colomns of TM60- and thrombin-Affi-gel, while the 94kDa fragment did not bind to either Affi-gel. When the same experiment was performed using chymotrypsin, three fragments (94kDa, 45kDa and 39kDa) were observed. On TM60- and thrombin-Affi-Gel columns, the smaller fragments (45kDa and 39kDa) were bound to both columns. However, on. thrombin-Affi-Gel column, 39kDa fragment was found in both unbound and bound fractions. It showed that the 45kDa fragment interacts with thrombin with a higher affinity than the 39kDa fragment. These results indicate that the thrombin-binding site is located on the "tail" portion of GPIba, especially on a chymotryptic cleavage site.Then 43kDa tryptic fragment was purified and its partial amino acid sequence was analyzed using gas phase amino acid sequence analyzer. Based on its amino acid sequence, several analogous oligopeptides were synthesized. Three peptides (#1-10, #11-23, #17-28) inhibited 0.05 U/ml thrombin-induced aggregations of washed human platelets in dose-dependent manners. IC50 were in the range of L50-550μM for each of these peptides.
A DEFINITION OF HEPARIN ANTICOAGULANT POTENCY APPLICABLE TO ALL HEPARINS AND HEPARIN-LIKE SUBSTANCES AND ITS PRACTICAL APPLICATION IN ASSAYING HEPARIN
Authors: Jackson Craig M 
Published: August 2018

Heparins increase the rate of inactivation of proteinases by antithrombin without being consumed in the inactivation reaction. The anticoagulant activity of any heparin or heparin preparation is thus determined by the increase in the inactivaton rate which it produces. This rate increase is dependent on the concentration of the heparin in the sample and on some now well known structural properties of the individual heparin molecules that produce high affinity for antithrombin . All proteinases are not inactivated by antithrombin equally rapidly in the absence of heparin, nor are heparins and heparin derivatives of different molecular weight equally effective in the inactivation of the same proteinase. Under appropriate conditions, the observed rate constant (kObs) for the heparin catalyzed proteinase inactivation reaction is simply related to the intrinsic potencies and concentrations of the individual high affinity heparin molecules in the sample. The intrinsic potency of a high affinity heparin molecule is the efficiency with which it catalyzes the inactivation of the particular proteinase, e.g. Factor Xa or thrombin, i.e., it is a second order rate constant, (designated k*) . After k* has been determined from kobs for a known heparin or heparin preparation and a particular proteinase, the concentration of heparin in an unknown sample can be calculated from the equation[H] = [HAT] = kobs/k*
In general terms, the appropriate conditions, i.e.,the antithrombin and proteinase concentrations, the pH, and ionic strength, required for this equation to be used are those conditions for which all of the high affinity heparin is bound to the antithrombin and pseudo first order kinetic behavior occurs. At very low heparin concentrations, a correction for the inactivation of the proteinase by antithrombin alone is necessary, but is easily made.Supported by Organon Teknika Corporation and an Established Investigator Award from the American National Red Cross
INDUCTION OF OSTEOPOROSIS IN RATS BY STANDARD HEPARIN AND LOW MOLECULAR WEIGHT HEPARIN
Authors: Mätzsch T , Berggvist D , Hedner U , Nilsson B , Østergaard P 
Published: August 2018

Long-term treatment with heparin can induce osteoporosis. This complication is suspected to be related to the dosage of heparin rather than to duration of therapy, but the mechanism by which heparin induces osteoporosis is unknown. In a previous study we reported the same degree of reduction in mineral bone mass in rats after treatment with 2 IU heparm/g bw for 33 and 65 days (Thromb Haemostas 1986,56:293-4). Using the same animal model we compared the effect of a high-dose standard heparin (SH) and a low molecular weight heparin (LMWH) in a high and a low dose on the mineral bone mass in the femur of rats.
Method: 60 female Wistar rats (207±1.8 g) were randomly allocated to treatment with either 2 Xal U/g bw of standard heparin (SH), 2 Xal U/g bw of LMWH ("high-dose"), 0.4 Xal U/g bw LMWH ("low-do-se") or placebo (saline). A standard sodium salt heparin of porcine origin was used, and the LMWH was an enzymatically depolymerized pork mucosal heparin (LHN-1, mean MW 4900 D). Treatment with s.c. injections was continued for 34 days. 24 hours after the last injection the rats were sacrificed and the carefully cleaned femora weighed in air and in water under standardized conditions. Volumes and densities were calculated from the weights. The bones were then incinerated for 48 hours at 600°C and weighed again to determine the ash content (expressed as ash weight per ml of unashed femur volume).
Results: There was a significant decrease in ash content (p<0.01) and density (p<0.01) of the femora in all heparin treated groups as compared with controls. High-dose LMWH caused the same reduction in bone mineral mass as standard heparin. Treatment with low-dose LMWH resulted in a significantly less pronounced reduction in ash content (p<0.001) and density (p<0.05) of the femora when compared with high-dose standard heparin and high-dose LMWH.
CONCLUSION: Daily injections of 2 Xal U/g body weight of standard heparin or low molecular weight heparin for 34 days causes the same degree of reduction of mineral bone mass in rats. The reduction of mineral bone mass in rats by treatment with low molecular weight heparin is dose dependent.
A CELLULAR RECEPTOR FOR UROKINASE-TYPE PLASMINOGEN ACTIVATOR
Authors: Belin D , Baccino D , Wohlwend A , Estreicher A , Hurate J , Vassalli J-D 
Published: August 2018

Recent cell biological and biochemical studies on the urokinase-type plasminogen activator (u-PA) have revealed an unsuspected property of this protein: it binds with high affinity and specificity to the plasma membrane of a number of cell types. Hence, while the interaction of tissue-type plasminogen activator (t-PA) with fibrin suggests a preferred role for this enzyme in the maintenance of fluidity of the extracellular milieu, the cellular binding of u-PA results in the focalisation of plasmin generation to the close environment of the cell surface; this appears as an optimal configuration if u-PA is to participate in the enzymatic events required for cell migration.The available information on the cellular binding of u-PA can be summarized as follows:1. Human monocytes-macrophages, monocyte-like cell lines, fibroblasts, and a variety of other cell lines all express u-PA binding sites. The number of u-PA binding sites on a given cell type may vary as a function of the functional state of the cells. In some cases all sites are occupied by “endogenous” u-PA.2. Binding does not require u-PA activity, and prou-PA binds with the same affinity as does the active enzyme.3. The Kd for u-PA binding is between 1 and 10×10-10 M. The binding site appears to be specific for u-PA.4. Binding requires the presence of the A chain of u-PA; the growth factor module of the A chain is involved in this interaction.5. Bound enzyme does not dissociate readily, nor is it rapidly endocytosed; most importantly, it retains catalytic activity.Studies in progress are aimed at further defining the u-PA determinants responsible for binding. In this context it is noteworthy that there is a tight species specificity of binding: human and murine u-PA, for instance, bind only to cells of the homologous species. Characterization of the u-PA binding site suggests that it is an integral membrane protein that includes at least one Mf 50.000 polypeptide chain.In addition to allowing for the peri-cellular focalisation of u-PA catalysed proteolysis, expression of the u-PA binding site provides a mecanism whereby one cell type can acquire membrane-bound u-PA activity following secretion of the (pro)enzyme by another cell population. A striking example of this is the binding of u-PA, synthesized by the epithelial layer of the male genital tract, to the head region of murine spermatozoa.
DIAGNOSIS OF DEEP VENOUS THROMBOSIS: NON-INVASIVE VS INVASIVE DIAGNOSTIC PROCEDURES
Authors: ten Cate J W , Huisman M V , Buller H R 
Published: August 2018

The clinical diagnosis of deep vein thrombosis (DVT) in symptomatic patients is unreliable. The need for objective diagnostic tests is widely acknowledged. Contrast venography in experienced hands is considered to be the reference method. This method is invasive, uncomfortable to the patient, not easily repeatable and expensive.For this reason several non-invasive tests have been developed and evaluated recently. Of the non-invasive tests impedance plethysmography (IPG) has been thoroughly evaluated in properly designed prospective clinical trials. Serial IPG in symptomatic outpatients is safe and effective. It was shown in longterm follow-up that anticoagulant treatment could be safely withheld in over 500 patients with repeatedly normal IPG (0.3-0.6% recurrence DVT). The specificity for proximal DVT was 92%. The feasability of IPG in symptomatic outpatients was over 95%. The safety of withholding anticoagulant treatment in symptomatic inpatients with a serial normal IPG is an unresolved issue. Preliminary results show that a similar sensitivity might be obtained in inpatients, however, the feasability was lower (87%).Doppler ultrasound has been studied extensively, however, there is a great variation in reported sensitivity for proximal DVT due to the lack of objective diagnostic criteria and the safety of withholding anticoagulant treatment in patients with serial normal Doppler tests results is not es tablished.strain gauge plethysmography has not been evaluated properly and therefore awaits further studies. 125I-fibrinogen legscanning has been shown to be sensitive for calf vein thrombosis (over 90%). In combination with IPG this method is a safe and effective alternative to venography.Radionuclide phlebography has never been evaluated in prospective clinical trials in a broad spectrum of symptomatic patients, and can therefore not be recommended for routine use.It is concluded that presently the management of patients with clinically suspected DVT should be performed with the use of serial IPG, IPG in combination with 125I—fibrinogen legscanning or contrast venog raphy.
A RANDOMISED DOSE RANGING STUDY OF TWO-CHAIN TISSUE-TYPE PLASMINOGEN ACTIVATOR (BW-t-PA) IN MYOCARDIAL INFARCTION: IN VITRO MONITORING
Authors: Kluft C , McNeill A , Adgey A A J , Rijken D C , Nieuwenhuizen W , Cohen A F 
Published: August 2018

In a randomised study, thirty patients with myocardial infarction received either 20, 50 or 100 mg recombinant BW-t-PA in 90 minutes. Blood samples were taken just before the infusion, and after 90 min. In vitro effects of t-PA were prevented by addition of 250 μg/ml polyclonal t-PA antibodies, which were shown to block in vitro actions of up to 5 μg t-PA/ml during plasma handling.There were dose related (MIU/kg/90 min) decreases of α2 -antiplas-min (AP, functional assay), plasminogen (PLG, streptokinase assay) and fibrinogen (FBG, Clauss) at 90 min (lineair regression: r = 0.67; 0.55 and 0.40, n = 30, all p < 0.05, resp.). Decreases for the 100 mg dose were for the respective components: 70 ± 10 (SD)%, 28 ± 7% and 33 ± 17% of pretreatment levels. The extent of the AP changes appeared to be the most sensitive parameters and these changes correlated with those in PLG and FBG. Pretreatment values of FBG were elevated (137 ± 37%) and at 90 minutes were 100 ± 23% of pooled plasma. Decreases in FBG were significantly (p < 0.001) correlated with absolute pretreatment levels, indicating preferential reductions of elevated levels of fibrinogen.Using our new enzymimmunoassays based on monoclonals for degradation products of fibrinogen (FDP), fibrin (FbDP) and the total (TDP), these products were measured in plasma (not serum). Before infusion 14 patients showed TDP levels (range: 0.5 - 2.3 μg/ml); at 90 min 29 patients (0.6 - 13 μg/ml. The increase in TDP accounted for only 0.75% (range up to 5.3%) of the apparent FBG reduction (Clauss) at 90 min. Detectable FbDP were generated in 24 patients at 90 min. For the two highest dosages the level (median 2.0 μg/ml) was significantly higher than at the dosage of 20 mg (median 0.85 μg/ml), indicating weaker fibrinolytic effect of t-PA at the lowest dosage. To evaluate the fibrinolytic/fibrinogenolytic effects of the t-PA the ratio FbDP/FDP was calculated. For the 50 mg dosage all ratios were ≥ 1; for 100 mg only 6 patients showed a ratio ≥ 1 at 90 min. This may indicate relative specific increase of fibrinogenolysis at higher dosages.
A RANDOMISED DOSE RANGING STUDY OF DOUBLE CHAIN TISSUE PLASMINOGEN ACTIVATOR (BW t-PA) IN ACUTE MYOCARDIAL INFARCTION: CLINICAL RESULTS
Authors: McNeill A D , Cunningham S R , Koster R , Bucknall C , Sponzilli C , Kluft K 
Published: August 2018

Despite extensive experimental use of t-PA in patients with acute myocardial infarction (AMI) a randomised dose ranging study has not yet been published. Fifty-five patients were randomised to BW t-PA 20 mg, 50 mg or 100 mg administered over 90 minutes. They received the drug 2.3 hours (range 0.3-4.3 hours) after the onset of AMI and underwent coronary arteriography to determine perfusion grade of the infarct related artery at 90 minutes. Responders were defined by TIMI perfusion grades 2 or 3. Response rates were:A logistic model fitted to the data showed the probability of reperfusion to increase in a dose related manner to 70%. Fibrinogen concentrations were measured in 30 patients and decreased to 83.6% of the preinfusion value at 90 minutes after 20 mg, to 76.2% after 50 mg and to 67.1% after 100 mg. There was a significant correlation between the dose of BW t-PA in megaunits/kg and consumption of fibrinogen at 90 minutes (p<0.05). This study indicates that thrombolysis with double chain t-PA proceeds in a dose related manner and that systemic fibrinogenolysis appears to be mild.