bluuebunny/crossref_metadata_2025 huggingface dataset:
Emerging Roles in Design Expansion: ‘The Third Group’ Involved in Design
Authors: Xiang Chen , Liu Wei
Published: July 2018

Design, regarded as the key factor of innovation, has evidently developed diversified designeruser relationships in order to release productivity. However, to further leverage design capabilities, ‘the third group’ of people who are neither design experts nor users will collaborate with designers through their expertise and fill the skill gap between designers and users. This study therefore aims to explore how ‘the third group’ form integral roles in the design expansion terrain. To address the research question, this study adopts semi-structured interview as the research method, through which 17 informants experienced in design practices without design background are investigated. Subsequently, the results are classified into five roles ‘the third group’ can play in the design collaboration with detail clarifications, which include ‘vision practitioner’ ‘business model designer’, ‘organization facilitator’, ‘language manipulator’ and ‘scenario composer’. Finally, the conclusion is set to contribute to identification of the design expansion terrain and the adaptive roles, which could be beneficial for non-design professionals to gain a position in design collaboration and also for designers to broaden abilities to collaborate across disciplines.
Research on Crowdsourcing Camera Mode System based on Block Chain Technology
Authors: Hu Dou , Ma Chuang , Gao Yuanlong , Liu Wenlong
Published: July 2018

As a new business model, the crowdsourcing camera mode has been paid close attention in recent years. However, traditional crowdsourcing operations rely too much on centralized institutions, which have many drawbacks. It is precisely because of this that the superiority of block chain technology is reflected. With the flourishing development of the Internet and the ever-changing block chain technology, this paper provides the research on crowdsourcing camera mode based on block chain technology from four aspects including the analysis of decentralization, the strengthen of security precautions, the establishment of appropriate systems and the gradually transition of token system.
Design of Service Framework Based on the Trip Experience of the Elderly – Take the cultural and historical scenic spot as an example
Authors: Meng Ying , Meng Kaining , Liu Jiahao
Published: July 2018

The tourism market that serves the aged is already being paid more and more attention to with the trend of population aging, but there is still no suitable mode for the tourism of the old in the view of sightseeing, visiting, nostalgia and other qualities. Based on existing relevant research, the author adopts questionnaire and interview survey, this paper analyzes the present travel intention and pain point of the elderly and then investigates the historical and cultural sights of the city with large passenger flow through field investigation method. By summarizing the common characteristics of individual cases, this paper analyzes the common problems existing in our country's humanistic and historical tourist attractions and constructs a service framework suitable for the elderly to visit the cultural and historical scenic spots to improve the existing deficiencies.
Periphere MR-Angiografie
Authors: Kramer Harald , Kreitner Karl-Friedrich
Published: June 2018

In der Diagnostik der peripheren AVK gilt die digitale Subtraktionsangiografie (DSA) immer noch als Referenzstandard. Alternativ stehen Sonografie, CTA und MRA zur Verfügung. Die im Folgenden vorgestellte MRA bietet ein breites Portfolio an verschiedenen Techniken und kommt damit für verschiedene Anwendungsmöglichkeiten infrage.
Wer profitiert von Stufenweisen Wiedereingliederungen zu Lasten der Deutschen Rentenversicherung? – Ergebnisse einer Kohortenstudie
Authors: Bürger Wolfgang , Streibelt Marco
Published: July 2018

Hintergrund Stufenweise Wiedereingliederungen (STW) haben für die Deutsche Rentenversicherung angesichts ihres Mengen- und Ausgabenzuwachs eine zunehmende Bedeutung im letzten Jahrzehnt. Daher stellt sich die Frage nach der Effektivität sowie geeigneten Zielgruppen bzw. Kontraindikationen für diese Leistung nach medizinischer Rehabilitation.

Methodik 40 262 Versicherte wurden vor Antritt und 15 Monate nach medizinischer Rehabilitation schriftlich befragt. Die Kontrollgruppe (KG) bildeten Versicherte ohne STW. Die Balancierung erfolgte mittels Propensity Score Matching. Die 3 primären Erfolgskriterien waren versicherungspflichtige Beschäftigung, Erwerbsminderungsrenten und Arbeitsunfähigkeitsdauer im Follow-up. Als sekundäre Outcomes wurden die körperliche und emotionale Rollenfunktion des SF-36 sowie die psychische Gesundheit mittels PHQ-4 definiert.

Ergebnisse Es konnten 1009 Paare gebildet werden. STW-Teilnehmer wiesen gegenüber der KG deutlich höhere Reintegrations- und geringere Frühberentungsquoten, günstigere Fehlzeitenverläufe sowie bessere körperliche und psychische Gesundheitsverläufe auf. Die Effekte waren in Gruppen mit hohem initialen Frühberentungsrisiko sowie langen Fehlzeiten vor der Rehabilitation besonders ausgeprägt.

Diskussion Die Ergebnisse liefern klare Hinweise für die Effektivität der STW im Anschluss an eine medizinische Rehabilitation. STW sind regelhaft indiziert bei Versicherten mit Fehlzeiten über 3 Monaten oder erhöhtem Frühberentungsrisiko (Screening-Instrument zur Messung des Bedarfs an berufsbezogenen Behandlungsangeboten in der medizinischen Rehabilitation, Werte>8). Kritisch sind STW bei Versicherten mit geringeren Fehlzeiten (12 Wochen und weniger) bzw. einem geringen Frühberentungsrisiko (SIBAR-Werte<6).
Iridium-Catalysed C–H Borylation of 2-Pyridones; Bisfunctionalisation of CC4
Authors: Campello Hugo , Gallagher Timothy , Honraedt Aurélien , Niwetmarin Worawat , Gotti Cecilia
Published: June 2018

The high regioselectivity associated with the iridium-catalysed borylation of pyridones has been exploited to provide a very direct and efficient entry to C(10) doubly substituted CC4 variants of cytisine. Two approaches have been evaluated based on (i) C–H activation of cytisine (or an N-substituted derivative) followed by N-alkylation (to enable dimer formation) and (ii) direct C–H activation and borylation of CC4 itself. Both approaches provide access to C(10)-functionalized CC4 derivatives, but direct borylation of CC4 allows for a wider range of functional group interconversions to be tolerated.
Non-Occlusive Bleeding Times May Improve the Value of Ivy Bleeding Times
Authors: Zeigler Zella R
Published: June 2018

The present studies measured bleeding times, without venous occlusion, in a series of patients, whose bleeding times (+ venostasis) consistently exceeded 20 min. During these tests, the amount of blood loss (expressed as mg/min) was also quantitated. To allow comparison, normal controls were studied before and following aspirin ingestion. In normal controls, the mean standard Ivy bleeding time was 5.0 with a range of 2.5 to 7.5 min. Two hours after aspirin (650 mg), this increased to 7.3 min (range 4.0−12.0). For comparison, the non-occlusive bleeding time averaged 3.8 min (1.0−6.5) and after aspirin 5.3 min (2.5−11.5). The measured amount of blood loss was 5.0 mg/min (0−10.5 mg/ min) under all of the above conditions. At the other extreme, patients with severe bone marrow failure had occluded and nonoccluded bleeding times in excess of 20 min. Moreover, these were often associated with excess blood loss. By contrast, patients with “Ivy” values >20 min in association with platelet counts >10,000/μl had unpredictable bleeding parameters. In the latter group, the non-occluded values ranged from 1 to >20 min. Of particular note, the non-occlusive times appeared to correlate with spontaneous bleeding manifestations. Only a rare patient (1/37), whose non-occluded value was <20 min, had worrisome bleeding. By contrast, serious bleeding manifestations were observed in 39% whose non-occluded value exceeded 20 min. This was even higher (64%) in those with a non-occluded value >20 min and excess blood loss. These studies provide laboratory and clinical evidence for the heterogeneous behavior of patients with venostasis bleeding times >20 min. These additional laboratory measurements may be helpful in defining risk of spontaneous bleeding and in evaluating therapeutic strategies in such patients. However, studies will need to be performed to correlate this type of information with bleeding associated with invasive diagnostic or surgical procedures.
Protein C Inhibitor and Other Components of the Protein C Pathway in Patients with Acute Deep Vein Thrombosis during Heparin Treatment
Authors: Tabernero D , España F , Vicente V , Estellés A , Gilabert J , Aznar J
Published: June 2018

The protein C inhibitor (PCI) concentration and other parameters of the protein C pathway were studied in 19 patients with symptomatic acute deep vein thrombosis before and during the first 5 days of heparin treatment. The mean levels of PCI antigen and activity decreased rapidly and significantly during the first day of heparin therapy from 83 and 81% to 60 and 59% of the pooled normal human plasma (p <0.01), respectively, and to 56 and 54% after 5 days of treatment (p <0.01). In contrast, antithrom-bin III decreased progressively 25% during 5 days of heparin treatment. Protein C antigen and activity and total protein S remained unchanged during heparin treatment. Free protein S was decreased before heparin treatment (83%, p <0.05) and increased to normal values after 5 days of treatment. C4b-binding protein was significantly increased before and during heparin treatment (p <0.01). Activated protein C (APC) complexed to its two major plasma inhibitors, PCI and α1-antitrypsin (α1AT) were measured by specific ELISA’s. Before treatment, 18 of the 19 patients studied had increased levels of APC: α1AT complexes with a mean value of 27 ± 22 ng/ml (range, 6−86 ng/ml) compared to normal values (8 ± 2 ng/ml) and 12 of the patients also had detectable APC:PCI complex levels with a mean value of 11 ±17 ng/ml (range, 5−68 ng/ml). Both APC:inhibitor complexes decreased significantly during heparin treatment.
A Synthetic Factor VIII Peptide of Eight Amino Acid Residues (1677-1684) Contains the Binding Region of an Anti-Factor VIII Antibody which Inhibits the Binding of Factor VIII to von Willebrand Factor
Authors: Foster Paul A , Fulcher Carol A , Houghten Richard A , Zimmerman Theodore S
Published: June 2018

The monoclonal anti-factor VIII (FVIII) antibody C4 has previously been reported to inhibit the binding of purified FVIII to immobilized von Willebrand factor (vWF). The binding area of C4 was identified to be within fifteen amino acid residues (1670-1684) based on the ability of a synthetic FVIII peptide consisting of amino acid residues 1670-1684 to completely inhibit the binding of C4 to FVIII. We now report the further localization of the binding region of C4 to within eight amino acid residues (1677-1684) of FVIII light chain. Nine new overlapping FVIII peptides were synthesized based on the amino acid sequence of the acidic region of FVIII light chain and tested, along with seven previously tested peptides, for the ability to inhibit C4 binding to FVIII in an ELISA assay. Three synthetic FVIII peptides 1670-1684, 1675-1690, and 1677-1684 demonstrated dose dependent inhibition of C4 binding to FVIII. The three reactive peptides contain residues 1677-1684 in common. Since C4 can completely inhibit the binding of FVIII to vWF, this report further localizes an eight amino acid residue region of FVIII which may be important in the mediation of vWF binding.
The Simultaneous Acute Release of Tissue-Type Plasminogen Activator and von Willebrand Factor in the Perfused Rat Hindleg Region
Authors: Tranquille N , Emeis J J
Published: June 2018

In perfused rat hindlegs, platelet-activating factor and bradyki-nin induced the acute release of both tissue-type plasminogen activator (t-PA) and von Willebrand Factor (vWF). The time course of release was similar for both proteins, and the amounts of t-PA and vWF released under various conditions were closely correlated. Release of both t-PA and vWF required extracellular calcium, and could be induced by the calcium ionophore A-23187. Protein synthesis was not required for release to occur.

Phorbol myristate acetate also induced release of t-PA and vWF, though with a different time course; DDAVP was inactive.

The results suggest that the release of t-PA, and that of vWF, are closely linked at the cellular level.
Interaction of a Plasmin A-Chain/t-PA B-Chain Hybrid Enzyme with Plasma Inhibitors In Vivo and In Vitro
Authors: Wilson S , Chamberlain P , Dodd I , Esmail A , Robinson J H
Published: June 2018

A hybrid plasminogen activator consisting of the “A” chain of plasmin linked to the “B” chain of rt-PA was inhibited in vitro in human and guinea pig plasmas 4 to 5-fold more rapidly than its parent activator, two-chain t-PA. Using zymographic and autoradiographic techniques together with the use of immunodepleted plasma the major inhibitor was identified as aIpha-2-antiplasmin. The pharmacokinetic profile of the hybrid in guinea pigs was determined by two different methods: disappearance of fibrinolytic activity and removal of radiolabelled hybrid from the circulation. Fibrinolytic activity was cleared rapidly via inhibitory mechanisms, whilst radiolabelled material was cleared considerably more slowly due to the formation of hybrid-inhibitor complexes. When the active site of the hybrid was reversibly acylated inhibitory mechanisms were evaded and a prolonged pharmacokinetic profile of activity was observed.
Deglycosylation Increases the Fibrinolytic Activity of a Deletion Mutant of Tissue-Type Plasminogen Activator
Authors: Wilhelm James , Kalyan Narender K , Lee Shaw Guang , Hum Wah-Tung , Rappaport Ruth , Hung Paul P
Published: June 2018

Δ2−89 t-PA is a deletion mutant lacking the finger (F) and epidermal growth factor (EGF) domains; thus, the fibrin interaction of this molecule must be mediated solely by the kringle region. In the present study, the influence of the oligosaccharide side-chains on the activity of Δ2−89 t-PA has been investigated. Δ2−89 t-PA was secreted in two forms, designated I and II, which presumably differ by the lack of one asparagine-linked oligosaccharide in the kiiugle 2 domain of form TT, Forms I and II of Δ2−89 t-PA weie puiified; form II displayed higher fibrinolytic activity than form I. When foini I was partially deglycosylated or treated to remove sialic acid, fibrinolytic activity was increased. Production of Δ2−89 in the presence of timicamycin led to secielion of a glyean-free activator with higher activity. These findings suggest that certain oligusacchaiide side chains, particularly (hose containing sialic acid, can interfere with the interaction between the kringle region of t-PA and fibrin.
Influence of Metoprolol Treatment on Sympatho-Adrenal Activation of Fibrinolysis
Authors: Larsson P T , Wiman B , Olsson G , Angelin B , Hjemdahl P
Published: June 2018

The effects of mental stress (a colour word conflict test, CWT) and adrenaline infusions (0.1 and 0.4 nmol kg−1 min−1) on t-PA activity, t-PA antigen, PAI-1 activity and PAI-1 antigen were studied in 18 healthy male volunteers. Furthermore, the effects of metoprolol (200 mg/day during 1 week) or placebo (double-blind cross-over study) on fibrinolytic responses to sympatho-adrenal activation, and relationships between fibrinolysis and blood lipids were investigated.

Low and high dose adrenaline infusions yielding plasma adrenaline levels of 0.9 ± 0.1 and 3.4 ± 0.4 nmol/1, respectively, dose-dependently increased t-PA levels with a concomitant decrease in PAI-1 levels. A similar, but weaker, fibrinolytic response seemed to occur during CWT when plasma adrenaline levels were only moderately increased (to 0.4 ± 0.1 nmol/1). Metoprolol treatment did not influence the resting levels of the fibrinolytic variables studied, but tended to enhance the t-PA response to CWT and further reduce PAI-1 during adrenaline infusion. Metoprolol treatment was not accompanied by any rise in PAI-1 levels despite drug induced elevations of triglyceride levels. Thus, the present study shows that sympatho-adrenal activation increases fibrinolytic activity in vivo and that meto prolol treatment may have a favourable influence on this activity.
Human Platelet Factor 4 and Its C-Terminal Peptides: Heparin Binding and Clearance from the Circulation
Authors: Rucinski Boguslaw , Niewiarowski Stefan , Strzyzewski Marian , Holt John C , Mayo Kevin H
Published: June 2018

Human platelet factor 4 (PF4), a high affinity heparin binding protein, is released from stimulated platelets and stored at vascular sites, predominantly in liver, from where it can be brought back into circulation by heparin. We attempted to define structural requirements for PF4 binding to heparin and for the pattern of its clearance from the circulation. Intact PF4 bound strongly to heparin agarose and was eluted at 1.4 M NaCl, while reduced PF4 and PF4 C-terminal peptides PF4 (47-70) and PF4 (58-70) bound weakly and were eluted at 0.2-0.5 M NaCl. 125I-radiolabeled intact PF4, reduced PF4 and C-terminal PF4 peptides injected into rabbits were cleared from the circulation in a biphasic pattern with components having half-life time of 1-2 min and 20-140 min. Heparin eliminated the fast component of PF4 clearance, but it did not affect clearance of reduced PF4 or C-terminal PF4 peptides. In contrast to reduced PF4 and PF4 (47-70), intact PF4 that accumulated in the liver and spleen, was displaced by heparin into circulating blood. In conclusion, specific binding sites and native conformation of the molecule are critical for high affinity PF4 binding to insolubilized heparin and for a pattern of PF4 clearance from the circulation in the presence of heparin.
Dilute aPTT Prolongation by Antiphospholipid Antibodies in Patients with Liver Cirrhosis
Authors: Violi Francesco , Ferro Domenico , Quintarelli Claudio , Alessandri Cesare , Saliola Mirella , Valesini Guido , Balsano Francesco
Published: July 2018

The behaviour of aPTT, as assessed by standard or diluted phospholipid mixture, was investigated in 20 patients suffering from liver cirrhosis. Standard aPTT was prolonged in 13 but it was corrected by 1:1 mixture with normal plasma. Dilute aPTT performed in samples mixed 1:1 with normal plasma and calculated by the difference in time between 1:80 and 1:5 phospholipid mixture was prolonged in 9 patients, who had also significantly higher titre of anticardiolipin antibodies (p <0.005). Unlike patients’ plasma with normal dilute aPTT, the addition of 0.05 M PC/PS liposomes to patient’s plasma with prolonged dilute aPTT significantly shortened dilute aPTT (p <0.001).

This study shows the presence of antiphospholipid antibodies in some patients with liver cirrhosis; this seems to be responsible for the prolongation of dilute aPTT.
The Comparative Effects of Recombinant Hirudin (CGP 39393) and Standard Heparin on Thrombus Growth in Rabbits
Authors: Agnelli Giancarlo , Pascucci Claudia , Cosmi Benilde , Nenci Giuseppe G
Published: July 2018

The aim of this study was to compare the ability of standard heparin and recombinant (r-)hirudin, a specific inhibitor of thrombin, to inhibit thrombus growth in a rabbit jugular vein model. Doses of standard heparin and r-hirudin equivalent in prolonging the aPTT were first identified. The ability of these doses to inhibit 125I-fibrin accretion onto preexisting thrombi was then evaluated. 0.5 and 0.75 mg/kg of standard heparin and 0.8 and 1.25 mg/kg of r-hirudin infused over 3 h produced a mean prolongation of the aPTT of 1.5 and 2 times, respectively. In saline treated rabbits 62 ± 7 μg of 125I-fibrin were accreted on the pre-formed thrombi. The lower doses of standard heparin and r-hirudin produced a 125I-fibrin accretion of 44 ± 5 and 25 ± 4 μg, respectively (p <0.01). The two higher doses of standard heparin and r-hirudin produced a 125I-fibrin accretion of 34 ± 4 and 17 ± 3 μg, respectively (p <0.01). The increase in the dose of standard heparin up to 2.5 mg/kg produced a 125I-fibrin accretion of 26 ± 3 μg, a 58% reduction when compared with saline. The increase in the dose of r-hirudin up to 5 mg/kg produced a 125I-fibrin accretion of 12 ± 2 μg, an 81% reduction when compared with saline. No further inhibition was observed when the doses of both agents were further increased. We conclude that doses of standard heparin and r-hirudin equivalent in prolonging the aPTT have a different effect on thrombus growth inhibition, r-hirudin being twice as effective as standard heparin. Exclusive inhibition of thrombin without any other inhibiting effect on blood coagulation appears to be sufficient to inhibit thrombus growth. Our results seem to be promising in view of a clinical evaluation of r-hirudin
Sample Size in the Planning and Interpretation of Clinical Trials
Authors: levine Mark N , Hirsh Jack
Published: June 2018

An understanding of sample size determination is important in both planning and interpreting the results of clinical trials. A Type II error occurs when it is concluded that there is no difference between treatment groups, when in truth there is a difference. Such a false negative conclusion results from too few patients in a trial. In this review the principles of estimating sample size before a trial is commenced and evaluating the results of a negative completed trial are reviewed. Clinically relevant examples are used to illustrate these concepts.
Characterization of Na+/H+ Exchange in Platelets
Authors: Livne Avinoam , Grinstein Sergio , Rothstein Aser
Published: June 2018

Acidification of the cytoplasm of human blood platelets leads to activation of Na+/H+ exchange. As a result, alkalinization occurs that is detectable by an intracellular fluorescent pH indicator. The activity of the exchanger can also be measured by the swelling of platelets suspended in Na-propionate medium using a Coulter Counter: the rapid entry of propionic acid leads to acidification and activation of Na+/H+ exchange with the parallel entry of Na+ and propionic acid leading to osmotic swelling. The Na+/H+ exchanger is sensitive to amiloride and to derivatives that are reported to be more specific inhibitors; it is specific for Na+ and Li+ with no measurable transfer of K+, Rb+ or Cs+; its Km for Na+ is 75 to 90 mM; it displays competitive behavior between Na+ and amiloride; its activity is decreased in cells loaded with Na+ by prolonged ouabain treatment; and it has a high temperature coefficient. These properties are in general similar to those of the exchanger in other cells. It is suggested that the Na+/H+ exchanger plays a role in platelet pH regulation.
Immunoradiometric Assay for the Calcium-Stabilized Conformation of Human Protein S
Authors: Poort S R , Deutz-Terlouw P P , van Wijngaarden A , Bertina R M
Published: June 2018

Rabbit polyclonal anti-protein S serum was fractionated with immobilized human protein S to establish solid-phase immunoradiometric assays recognizing Ca(II)-dependent and NonCa(II)-dependent epitopes of human protein S. The two assays were specific for PS:Ca(II)Ag and PS:NonCa(II)Ag and highly sensitive with a lower limit of detection of about 2.5 ng/ml.

PS:Ca(II)Ag and PS:NonCa(II)Ag levels were measured in immunopurified protein S, thrombin-modified protein S and chy-motrypsin-cleaved protein S. Only in chymotrypsin-cleaved protein S an important discrepancy between the two antigen levels was observed.

Ranges for the concentration of PS:Ca(II)Ag and PS:NonCa(II)Ag and their ratio were established in plasma of healthy individuals (0.92 ± 0.13 U/ml, 0.98 ± 0.21 U/ml, 0.96 ± 0.17, respectively). In a group of patients using oral anticoagulant therapy the ratio PS:Ca(II) Ag/PS : NonCa(II)Ag decreased at increasing intensity of anticoagulation suggesting the presence of sub- and noncarboxylated protein S molecules.

In plasma of patients with a hereditary type I protein S deficiency PS:Ca(II)Ag and PS:NonCa(II) Ag were reduced to the same extent: mean ratio 1.02 ± 0.12 in the group not on oral anticoagulant treatment and 0.94 ± 0.10 in the group on oral anticoagulant therapy. Analysis of patients with a history of unexplained thrombo-embolic disease did not reveal individual patients with a PS:Ca(II)Ag/PS:NonCa(II)Ag ratio below the lower limit of the normal range (mean ratio 1.05 ± 0.17), suggesting that the frequency of genetic protein S variants with defects in the Ca(II)-stabilized conformation is very low.
Antithrombin III: Biodistribution in Healthy Volunteers
Authors: Knot E A R , Jong E de , Cate J W ten , Gie Liem Kian , van Royen E A
Published: June 2018

Five healthy volunteers were injected intravenously with 73-90 uCi purified human 131I-Antithrombin III (AT III), specific biological activity 5.6 U/mg. The tracer data were analysed using a three compartment model. The plasma radioactivity half life was 66.2 ± 1.2 (sem) h, the fractional catabolic rate constant of the plasma pool was 0.025 ± 0.002 (sem) h-1. These data were comparable with those described in the literature. Because of the difficulty in translating the mathematical analysis of various compartments into the biological model, biodistribiition was monitored by a gamma camera linked to a DEC PDF 11/34 computer system. Dynamic and static images were obtained at fixed time intervals following the injection of 131I-AT III.

Whole body scanning at intervals between the time of injection (t=0)and t=24.5 h showed 131I-AT III distribution over the heart, lungs, liver, spleen and great vessels. Dynamic scanning was performed over the heart, spleen and liver. Overlayed frames in the first ten minutes after the 131I-AT III injection showed the following radioactivity expressed as percentage of the injected dose; 5.9% ± 0.3(sem) over the heart, 10.6% ± 0.9 (sem) over the liver and 1.1% ⊥ 0.1(sem) over the spleen.

A slower decline of the radioactivity between t = 0 and t = 24 h; (19%) was measured over the liver compared with the radioactivity disappearance over the heart region. This shows, in combination with the fact that the radioactivity disappearance over the heart was identical with the radioactivity decline measured in the plasma samples that retention of 131I-AT III occurred in the liver. Heparin iv injected 6 h after the 131I-AT III injection in two volunteers induced a sharp increase of radioactivity over the liver region during the scanning demonstrating that heparin enhances the 131I-AT III uptake in the liver.
Intravenous and Subcutaneous Administration of Desmopresssin (DDAVP) to Hemophiliacs: Pharmacokinetics and Factor VIII Responses
Authors: Mannucci P M , Vicente V , Alberca I , Sacchi E , Longo G , Harris A S , Lindquist A
Published: June 2018

When desmopressin (DDAVP) is given to mild and moderate hemophiliacs intravenously (i. v.) or subcutaneously (s.c.), there is a very large between-patient variability for peak levels of factor VIII coagulant activity (VIII :C). To evaluate whether or not between-patient variability is related to DDAVP levels achieved in plasma, we measured drug levels in 14 hemophilic volunteers (VIII: C 2 to 31 U/dL) who were randomly given 0.3 μg/Kg of i. v. or s. c. DDAVP and crossed-over to the other treatment after an interval of 15–30 days. Peak DDAVP levels (Cmax) were higher for i.v. DDAVP (p <0.02), times to peak levels (tmax) were shorter for i.v. DDAVP (p <0.001). There was no difference between the i.v. and s.c. routes for plasma DDAVP time curve (AUC) and half-life (ti/,), but there was much larger variability for pharmacokinetic parameters with i.v. than with s.c. DDAVP. Post-DDAVP VIII:C increased 3.4 ± 1.6 fold (i.v.) and 3.3 ±1.3 fold (s. c.) over baseline levels, with no significant correlation between peak VIII :C and DDAVP levels for either route of administration. These findings establish the s. c. route of DDAVP administration to be bioequivalent in effect to the i.v. route, albeit with less variability. At the DDAVP dosage used in this study and currently recommended for therapy, the VIII: C response is neither a function of the rate of absorption of the compound nor of the magnitude of its plasma concentration.
Circulating Activities During Constant Infusion of Heparin or a Low Molecular Weight Derivative (Enoxaparine): Failure to Demonstrate any Circadian Variations
Authors: Toulon P , Vitoux J F , Leroy C , Lecomte T , Roncato M , Motobashi Y , Aiach M , Fiessinger J N
Published: June 2018

We compared in six patients successively treated with an unfractionated heparin (UFH) and a low molecular weight heparin (LMWH) the variations in plasma anti-Xa activity, measured in a chromogenic assay, during a 36 h constant infusion. The values varied in a wider range during UHF infusion, but remained in the therapeutic range except once in one patient. No circadian rhythm could be demonstrated in our six patients. LMWH infusion yielded very constant anti-Xa circulating activities. In both cases, there were no significant modifications of three proteins with high heparin affinity (antithrombin III, heparin cofactor II, histidine-rich glycoprotein).

Our results suggest that the circadian rhythm of the biological activities previously observed in patients treated with constant heparin infusion using clotting method is due to other factors than heparin itself.
Endothelial Cells and Normal Circulating Haemopoietic Cells Share a Number of Surface Antigens
Authors: Favaloro Emmanuel J , Moraitis Nick , Koutts Jerry , Exner Thomas , Bradstock Kenneth F
Published: June 2018

Human endothelial cells, cultured from umbilical cord veins, have been evaluated for expression of a large number of cell surface antigens with known haemopoietic, particularly myeloid, cell distribution. This was achieved by evaluating endothelial reactivity (using non-fixed cells) with groups of monoclonal antibodies (MAB) belonging to distinct Clusters of Differentiation (CD), as defined by the Third International Workshop on Leukocyte Differentiation Antigens (ILWS). Results indicate that many antigens known to be present on haemopoietic cells, including those on platelets, are co-expressed on endothelial cells. The most intense degree of reactivity was seen using MAB to CD-9 and CD-13, although significant reactivity was also observed using MAB to CD-31 and CD-32. Data also suggests weak binding to endothelial cells of MAB belonging to CD-14, CD-15 and CD-16. A number of unclustered MAB reactive with haemopoietic antigens can also be shown to bind to endothelial cells.
In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin
Authors: Rand Margaret L , Gross Peter L , Jakowec Donna M , Packham Marian A , Mustard J Fraser
Published: June 2018

Ethanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.
Prostacyclin and Thromboxane Production by Autogenous Femoral Veins Grafted into the Arterial Circulation of the Dog
Authors: de Castellarnau C , Cullare C , Lopez S , Bonnin O , Montesinos A , Guix M , Rutllant M LL
Published: June 2018

Vascular prostacyclin (PGI2) production is different in the arteries and veins of the dog. Experiments were performed to determine whether chronic grafting of the femoral vein into the arterial circulation would alter the normal PGI2 and thromboxane (TxA2) synthesis of the “arterialized” veins. Spontaneous and arachidonic acid (AA) stimulated PGI2 and TxA2 production (measured by radioimmunoassay of 6-keto PGF1α and TxB2 respectively) were analysed in full thickness punch biopsies of the middle part of the grafts after 3 and 16 months and compared with unoperated veins and arteries. PGI2 production was significantly higher in arteries than in veins but no significant difference in TxB2 production was found. Middle “arterialized” venous graft produced significantly lower amounts of PGI2 and higher amounts of TxB2 than unoperated vessels. PGI2 production was more reduced in the distal than in the middle or the proximal parts of the venous grafts especially when stimulated with AA. These findings do not support the concept that the venous graft was biochemically adapted or “arterialized” in terms of PGI2 production when implanted for 3 months or longer. Rather the markedly decreased PGI2/TxB2 ratio in the middle of the graft may be a contributory cause of thrombogenicity and may be implicated in the pathogenesis of neointimal hyperplasia.
Heparin Inhibition of Endotoxin-Dependent Limulus Amebocyte Lysate Coagulation
Authors: Marcum James A , Levin Jack
Published: June 2018

Addition of commercial heparin to preparations of the coagulation system obtained by hypotonic lysis of Limulus amebocytes, prior to the addition of endotoxin from gram-negative bacteria, inhibited gelation. Activation of the cell-lysate proclotting enzyme, utilizing a diluted lysate preparation and synthetic substrates, was inhibited to a comparable extent with either anticoagulantly active or inactive heparin. Other glycosaminoglycans, including heparan sulfate, dermatan sulfate, chondroitin 4-sulfate, and chondroitin 6-sulfate, did not inhibit the generation of clotting enzyme activity. Experiments conducted with preparations of proactivator(s) and proclotting enzyme, obtained by fractionation of lysate with heparin-Sepharose, revealed that inhibition of endotoxin-dependent activation of amebocyte lysate by heparin is mediated by precipitation of the proactivator(s) and can be prevented by increasing the salt concentration.
Effect of the Lupus Anticoagulant on Endothelial Fibrinolytic Activity In Vitro
Authors: Francis Robert B , Neely Sara
Published: June 2018

We investigated the effect of plasma and serum from 10 subjects with the lupus anticoaguiant and thrombosis and 9 normal subjects on the secretion of tissue-type plasminogen activator (t-PA) and its rapid inhibitor (type 1 plasminogen activator inhibitor, or PAI-1) by cultured human endothelial cells. Confluent monolayers of human umbilical vein endothelial cells were incubated for 48 hours with plasma or serum diluted ten-fold in serum-free endothelial cell growth medium, and the secretion of t-PA and PAI-1 measured by enzyme-linked immunosorbent assay. No consistent differences in mean t-PA and PAI-1 release were found between cells exposed to normal plasma or serum and plasma or serum from subjects with the lupus anticoagulant and thrombosis. No plasma or serum sample produced consistent inhibition of t-PA release or stimulation of PAI-1 release (defined as t-PA levels less than the mean minus two standard deviations for normal subjects, and PAI-I- levels greater than the mean plus two standard deviations for normal subjects, respectively). These findings do not support a role for altered endothelial fibrinolytic activity in the pathogenesis of thrombosis in subjects with the lupus anticoagulant, and are consistent with previous observations that these subjects have normal fibrinolytic activity in vivo.
High Levels of Plasma FVIII and vWF in the Toxic Epidemic Syndrome Patients
Authors: López-Fernández M F , López-Berges C , Fermoso J , Martín-Pascual A , Sánchez-Hernández J J , López-Borrasca A , Batlle J
Published: June 2018

Factor VIII and von Willebrand factor proteins were evaluated in 115 patients having the chronic phase of the Toxic Epidemic Syndrome (TES), a new multisystemic disease probably caused by the ingestion of denatured rapeseed oil, and in 50 control volunteers. Higher circulating levels of factor VIII procoagulant activity (VIII :C) (158 ± 58.4 U/dl), von Willebrand factor antigen (vWF: Ag) (166.1 ± 55.5 U/dl) and von Willebrand factor ristocetin cofactor activity (vWF:RCo) (178.7 ± 55.2 U/dl) were seen in TES patients (p < 0.001, TES patients versus control subjects, for each parameter). The increased levels of vWF:Ag and vWF:RCo observed in TES patients correlated with the scleroderma like lesion of the skin, with the sicca syndrome and with Raynaud's phenomenon (p < 0.01), but not with other clinical manifestations. The multimeric analysis of vWF in 92% of the TES patients was similar to that found in normal plasma, but in the remaining 8% a very slight increase of larger vWF multimers in plasma were observed. The raised levels of vWF found in TES patients in the chronic phase may reflect an “in vivo” vascular injury.
Single-Chain and Two-Chain Tissue-Type Plasminogen Activator (t-PA) Bind Differently to Cultured Human Endothelial Cells
Authors: Aerts Rob J , Gillis Karin , Pannekoek Hans
Published: June 2018

It has recently been shown that the fibrinolytic components plasminogen and tissue-type plasminogen activator (t-PA) both bind to cultured human umbilical vein endothelial cells (HUVEC). After cleavage of t-PA by plasmin, “single-chain” t-PA (sct-PA) is converted into “two-chain” t-PA (tct-PA), which differs from the former in a number of respects. We compared binding of sct-PA and tct-PA to the surface of HUVEC. Removal of t-PA bound to HUVEC by a mild treatment with acid and a subsequent quantification of eluted t-PA both by activity- and immunoradiometric assays revealed that, at concentrations between 10 and 500 nM, HUVEC bind about 3-4 times more sct-PA than tct-PA. At these concentrations, both sct-PA and tct-PA remain active when bound to HUVEC. Mutual competition experiments showed that sct-PA and tct-PA can virtually fully inhibit binding of each other to HUVEC, but that an about twofold higher concentration of tct-PA is required to prevent halfmaximal binding of sct-PA than visa versa. These results demonstrate that sct-PA and tct-PA bind with different affinities to the same binding sites on HUVEC.
Monoclonal Antibodies Directed to the Calcium-Free Conformation of Human Protein S
Authors: Marcovina Santica , Coppola Raffaella , Valsecchi Carla , Zoppo Adele , Gelfi Cecilia , Mannucci Pier Mannuccio
Published: June 2018

Four mouse hybridomas secreting monoclonal antibodies specific for human protein S (PS) have been generated. The antibodies, all of the IgG1 subclass, were designated S2, S3, S8, and S10. In a fluid phase radioimmunoassay, the binding of monoclonal antibodies to PS was about 30% greater in the presence of EDTA and totally inhibited in presence of Ca2+. Using the same technique, we performed displacement curves of 125I-labeled PS by purified PS, thrombin-cleaved PS, normal plasma, plasma from a patient on warfarin therapy, and plasma from a patient with no free PS and only PS bound to C4b-binding protein. The slopes of the curves show that the monoclonal antibodies reacted equally with all the tested forms of PS indicating that the antigenic site(s) to which the monoclonal antibodies are directed are present and exposed in free and bound PS, in thrombin-cleaved PS, and in the coumarin form of the protein. Each EDTA-dependent antibody, immobilized on Sepharose 4B-CNBr was used to purify PS from the barium citrate-absorbed, ammonium sulphate-soluble fraction of plasma. The fraction eluted from the immunoabsorbent with a buffer containing 4 mmol/1 CaCl2 and analysed by SDS-PAGE, contained two bands, one migrating with conventionally purified PS and the other with purified C4b-binding protein. Homogeneous PS was obtained by chromatography of the barium citrate absorbate on a DEAE-Sephadex column. The protein peak containing the bulk of PS was subsequently applied to the immunoadsorbent and eluted with 4 mmol/1 CaCl2. These studies demonstrate that EDTA-dependent monoclonal antibodies can simplify the isolation of PS from human plasma.
Von Willebrand Factor Multimer Patterns in Pregnancy-Induced Hypertension
Authors: Brenner B , Zwang E , Bronshtein M , Seligsohn U
Published: June 2018

Microangiopathy and disseminated platelet aggregation have been reported in thrombotic thrombocytopenic purpura (TIP) and pregnancy-induced hypertension (PIH). Since unusually large von Willebrand factor (vWF) multimers have been implicated in the evolvement of TTP, we analyzed factor VIII/vWF parameters in patients with PIH. Mean vWF: Ag level was significantly higher in 27 patients with PIH as compared to 20 matched healthy pregnant women (358 ± 160 u/dl vs. 274 ± 125 u/dl, p < 0.05). Moreover, plasma vWF: Ag levels and the ratio of vWF: Ag to factor VIII were found to be linearly correlated to the severity of PIH. In contrast, no significant differences in mean levels of factor VIII and ristocetin cofactor were observed between these groups. Crossed immunoelectrophoresis of vWF revealed a higher incidence of a pre-peak and an increased migration index in the PIH group as compared to the control group (60% vs. 44% and 1.27 ± 0.26 vs. 1.19 ± 0.18, p < 0.01 respectively). Analysis of plasma vWF multimer patterns by 1.4% agarose electrophoresis in 0.1% SDS revealed excessive amounts of large, medium and small size multimers in the PIH patients. Conceivably, the quantitative changes in vWF multimers reflect endothelial injury and may play a role in the microangiopathy observed in PIH.
Plasminogen Activator Inhibitor 1: Biosynthesis and mRNA Level Are Increased by Insulin in Cultured Human Hepatocytes
Authors: Kooistra T , Bosma P J , Töns H A M , van den Berg A P , Meyer P , Princen H M G
Published: June 2018

Clinical studies have shown that plasma insulin levels are closely related to plasma plasminogen activator inhibitor 1 (PAI-1) levels. To investigate a possible involvement of hepatocytes we have studied the effect of insulin on PAI-1 production by primary cultures of human hepatocytes. We have isolated human hepatocytes from seven left liver lobes. PAI-1 activity measured in 24 hours conditioned medium varied considerably between the various hepatocyte preparations (from 2.9 to 8.5 units per 5 cm2of cells) possibly as a result of interindividual variability in basal PAI-1 production by hepatocytes from different donors. In all cases, however, the relative extent, time profile and dose-dependency of the insulin-induced increase in PAI-1 synthesis were consistent. Up to about 7 nM, insulin dose-dependently increased both PAI-1 activity and PAI-1 antigen production. The increase in PAI-1 synthesis became measurable between 4 and 8 hours after addition of the hormone, and maximally reached twofold control values. The increase in PAI-1 synthesis could be fully explained by a concomitant increase in PAI-1 mRNA levels. The effect of insulin seems fairly specific for the synthesis of PAI-1: overall protein synthesis and mRNA levels of some control proteins (albumin and fibrinogen) did not markedly change after insulin addition. These results, obtained with primary cultures of human hepatocytes, are fully comparable with those obtained with the hepatocellular carcinoma cell line Hep G2. They strengthen the suggestion that the elevated level of PAI-1 in high insulin plasma might be the result of increased hepatic synthesis of PAI-1.
Poor Compliance Is a Major Factor in Unstable Outpatient Control of Anticoagulant Therapy
Authors: Kumar S , Haigh J R M , Rhodes L E , Peaker S , Davies J A , Roberts B E , Feely M P
Published: June 2018

Control of oral anticoagulant therapy in outpatients is often unsatisfactory. The contribution of poor compliance with prescribed warfarin to unstable anticoagulant control was investigated prospectively using low-dose phenobarbitone as an indicator of compliance in 30 out-patients, 15 with stable and 15 with unstable control. Following entry to the study, there was no significant change in anticoagulation (p = 0.36) in the group with stable control. In the group who previously had unstable control, there was a significant change in INR (p = 0.0045) and anticoagulant control greatly improved. It appears that the considerable fluctuation in INR seen in many of the latter patients before the study was due to poor compliance and that entering them into the study modified their behaviour. Two patients in this group who continued to have unstable anticoagulant control were shown to be poorly compliant using the phenobarbitone indicator. The results suggest that, in outpatients, poor compliance is the major cause of unstable anticoagulation with warfarin.
Changes of Plasma Coagulation and Fibrinolysis in Response to Mental Stress
Authors: Jern Christina , Eriksson Elsa , Tengborn Lilian , Risberg Bo , Wadenvik Hans , Jern Sverker
Published: June 2018

To study the effects of standardized mental stress (arithmetic and the Stroop color word test) on plasma coagulation and fibrinolysis, blood samples were obtained before, during, and after 20 minutes of mental stress from 10 healthy, non-smoking young males aged 22 to 30 years. Reactions were compared with those observed during physical exercise and infusion of adrenaline. Both von Willebrand factor antigen and factor VIII coagulant activity increased significantly in response to mental stress (95 ± 28 vs 123 + 56%; p <0.05 and 125 ±54 vs 217 ± 170%; p <0.05, respectively). There was also a significant increase of factor VII coagulant activity (86 ± 31 vs 108 + 51%; p <0.05). Furthermore, mental stress caused an activation of the fibrinolytic system with an elevation of tissue plasminogen activator activity and tissue plasminogen activator antigen (0.80 ± 0.48 vs 1.23 ± 0.96 IU/ml; p = 0.076 and 4.38 ± 1.87 vs 5.78 ± 2.58 IU/ml; p <0.01). Fibrinogen concentration increased during stress (1.95 ± 0.29 vs 2.11 ± 0.27 g/1; p <0.05). Similar but more pronounced responses were observed during exercise and adrenaline infusion. Parallel to the increases in coagulation and fibrinolytic factors there were significant increases in heart rate, and systolic and diastolic blood pressure. It is concluded that mental stress has significant effects on plasma coagulation and fibrinolysis, and that it could thus affect important risk factors for cardiovascular disease.