bluuebunny/crossref_metadata_2025 huggingface dataset:
Features of road-climatic zoning of territories
Authors: Efimenko Vladimir , Efimenko Sergey , Sukhorukov Alexey
Published: June 2018

The paper reflects the Russian and foreign experience of road-climatic zoning. It demonstrates the need to refine the applicable taxonomic zoning system using the taxonomic scheme “zone – subzone – road district”. When creating a database for road-climatic zoning, the authors of this paper, in contrast to the scheme adopted in Russia and abroad, take into account territorial patterns of water and heat processes that occur in road structures. The paper justifies soil characteristics for designing pavements in the study area.
Strength of tensed and compressed concrete segments in crack spacing under short-term dynamic load
Authors: Galyautdinov Zaur
Published: June 2018

Formation of model describing dynamic straining of reinforced concrete requires taking into account the basic aspects influencing the stress-strain state of structures. Strength of concrete segments in crack spacing is one of the crucial aspects that affect general strain behavior of reinforced concrete. Experimental results demonstrate significant change in strength of tensed and compressed concrete segments in crack spacing both under static and under dynamic loading. In this case, strength depends on tensile strain level and the slope angle of rebars towards the cracks direction. Existing theoretical and experimental studies estimate strength of concrete segments in crack spacing under static loading. The present work presents results of experimental and theoretical studies of dynamic strength of plates between cracks subjected to compression-tension. Experimental data was analyzed statistically; the dependences were suggested to describe dynamic strength of concrete segments depending on tensile strain level and slope angle of rebars to cracks direction.
Modifying admixtures to cement compositions produced from local raw materials
Authors: Vasileva Daria , Protodiakonov Egor , Egorova Anastasia , Antsupova Svetlana
Published: June 2018

Durability of hardened cement paste depends on chemical and mineralogical composition of Portland cement. The main factor for hardened cement paste is higher content of calcium aluminate and free calcium hydroxide, binding of which into water-insoluble compounds causes increase in resistance to water, frost and corrosion. The purpose of this research is to develop modifying admixtures to cement compositions based on local raw material - rock sand. Chemical and mineralogical properties of the source materials were studied using X-ray spectroscopy and X-ray diffraction analysis. Standard methods were used for defining physico-mechanical properties of sand and binder. Influence of the degree of mechanochemical activation of modifying admixture on the properties of binder and hardened cement paste made on its basis was studied. Research methods of scanning electron microscopy and spectral measurements were applied. The possibility of using admixture based on rock sand as a modifier was determined, its usage providing increase of strength, sulphate and frost resistance, which causes higher durability of cement concrete.
Thermal insulation coating based on water-based polymer dispersion
Authors: Panchenko Iuliia , Akulova Marina , Panchenko Dmitrii
Published: June 2018

For Russia, due to its long winter period, improvement of thermal insulation properties of envelope structures by applying thermal insulation paint and varnish coating to its inner surface is considered perspective. Thermal insulation properties of such coatings are provided by adding aluminosilicate microspheres and aluminum pigment to their composition. This study was focused on defining the effect of hollow aluminosilicate microspheres and aluminum pigment on the paint thermal insulation coating based on water-based polymer dispersion and on its optimum filling ratio. The optimum filling ratio was determined using the method of critical pigment volume concentration (CPVC). The optimum filling ratio was found equal to 55%.
Hardened cement paste microstructure as the main factor of concrete durability
Authors: Shuldyakov Kirill , Kirsanova Alena , Kramar Lyudmila , Trofimov Boris
Published: June 2018

When studying durability of concrete the main emphasis is put on its resistance to frost, water and sulphate, which depends on type, dispersion and stability of cement hydration products. The paper focuses on interrelation between strength, open porosity and peculiarities of microstructure of hydrated phases and their crystallization tendency under cyclic and chemical actions. In order to find out these dependences, the following parameters were defined in compliance with standards: open porosity of concrete by water absorption, compressive and tensile strength in bending, frost resistance and sulphate resistance. Methods applied in the research are X-ray diffraction analysis and scanning electron microscopy. The most promising structure of hardened cement paste for obtaining modern paving concrete is the one formed by weakly crystallized gel phases of type C-S-H(I) which are resistant to crystallization and provide stability and durability of concrete. One of the most used methods to obtain such structure is addition of compounds containing activated pozzolanic materials and superplasticizers.
Investigation of magnesium oxychloride cement at the initial hardening stage
Authors: Averina Galina , Chernykh Tamara , Orlov Aleksandr , Kramar Lyudmila
Published: June 2018

The paper investigates the process of variation of magnesium oxychloride cement deformations at the initial hardening stage depending on the activity of magnesium oxide powder which is determined by the parameters of the source material burning. Investigation is focused on magnesium cements obtained from pure magnesium hydroxide. Source materials were burnt at various temperatures with the purpose to obtain magnesium oxide powder with different activity. Regular content of hydrated phases was determined in hardened magnesium cement prepared on the basis of binders with different activity. The study reveals the influence of magnesium oxide powder activity on the process of deformation occurrence in hardened magnesium cement and its tendency to crack formation.
Building ceramics based on composition of low-quality clay and slurry
Authors: Guryeva Viktoriya , Doroshin Alexander , Andreeva Yuliya
Published: June 2018

At present, there is a trend towards increasing demand for ceramic products with enhanced physical and mechanical properties. This study is aimed at developing scientifically grounded compositions of ceramic products that maximize the use of local low-quality aluminosilicate raw materials and secondary raw materials in brick-making technology. Characteristics of local low-melting clays and industrial waste in the form of drilling slurry with minimum percentage of petroleum product were studied and presented in this paper. Standard methods for determining physical and mechanical properties of bricks, physicochemical and statistical methods of research are used as a methodological framework. The paper shows effects of drilling slurry with an increased content of calcium oxide on the composition, physical and mechanical properties of wall ceramics, as well as effects of composition of low-quality local clays and slurries on the structure and properties of ceramic materials. The modifying role of container glass and its effects on properties of a synthesized ceramic piece were studied and presented.
Narrow-aperture electron beam in the forevacuum pressure range as a tool for dimensional processing of silica glass
Authors: Zenin Aleksey , Klimov Aleksandr , Bakeev Ilya
Published: June 2018

The paper gives overview of the results of using narrow-aperture electron beam generated by a forevacuum plasma electron source as a tool for treatment of electrically non-conductive materials, such as technical glass. Effectiveness of electron beam treatment of non-conductive materials is caused by almost complete neutralization of target charge on the treated surface. Charge neutralization occurs due to ion flow from beam plasma generated while transporting the beam through forevacuum pressure area. The study demonstrates the possibility to control depth and form of milling by changing modes of electron beam treatment. Combined use of electron beam and automated system for beam deflection and sweep makes possible to perform dimensional processing, particularly cutting and milling with complex trajectory. Milling rates were experimentally found depending on treatment time and mode. The suggested method of silica glass treatment represents an alternative for traditional treatment methods.
Housing sector development in socio-economic space of agglomeration
Authors: Podoprigora Yulia , Volchkova Irina , Danilova Maria , Ufimtseva Evgeniya
Published: June 2018

The paper is aimed at studying the influence of balanced housing sector development on the cohesion level of the socio-economic space (SES) in agglomerations. Statistical and comparative analytical techniques are used as the basic methods in this research. The paper presents indicators that measure the level of integration and balance in the housing sector. It proposes a set of mechanisms aimed at promoting a more balanced development of the housing sector in order to achieve SES cohesion in the Tomsk agglomeration. The relevance of the study is associated with intensification of agglomeration processes and the need for new methods and techniques to assess the balanced state of housing sector development in agglomeration SES.
Surface models of granular materials in storage tanks
Authors: Zamyatin Nikolaj , Makovkin Vladimir , Smirnov Gennadij
Published: June 2018

The paper focuses on the problem of measuring the volume of granular materials in storage tanks where, due to uneven surfaces of these materials, the error in measurement by conventional methods reaches 15–20 percent. To increase the accuracy of volume measurement, a technique for modeling surfaces formed by granular materials in tanks is proposed.
Analysis of drinking water quality from the standpoint of health risks
Authors: Nikiforova Valentina , Vidishcheva Elena
Published: June 2018

The paper presents a hygienic quality assessment of water from sources in the Irkutsk Region (Russia) used for public drinking water supply. The aim of the study is to assess health risks to the population of Bratsk and the Bratsk District, which is associated with the exposure to chemicals coming with drinking water from the public water supply system. Risk of occurrence and development of non-carcinogenic effects is assessed for separate age groups using a special method. Based on the risk assessment methodology, non-carcinogenic risks for children and adults are described in quantitative terms. The total health risk of the test groups associated with the oral intake of chemicals with drinking water is estimated as negligible and, therefore, does not need to be reduced through additional measures. Lead and fluoride contents in drinking water are the major contributors to the risk level (59.5–68.4%). There is a risk of developing blood disorders and cardiovascular diseases in children of Bratsk (HI = 1.19), as well as bone tissue and teeth disorders in children of Bikey village, Bratsk District (HI = 1.10).
Third mandibular molar coronectomy: a way to prevent iatrogenic inferior alveolar nerve injuries—an systematic review
Authors: Lenfant Benoît , Haese Kevin , Kimakhe Said , Lesclous Philipe
Published: June 2018

Introduction: In the field of oral and maxillo-facial surgery, the avulsion of third mandibular molar is a very common procedure. However, and although the injury on the alveolar inferior nerve is very rare, the neurological risk must not be underestimated. Indeed, it may lower the patient’s quality of life in a significant way. The coronectomy is a technique that allows us to avoid this risk. It consists in remaining in place the third mandibular molar’s roots. Educational objectives: After a clinical introduction to this surgical technique, the main characteristics of this type of procedure will be presented with the help of an exhaustive literature review. Thus, we will refer to the following subjects: the obvious decrease of neurological risks, the potential pre and post-operating complications, the potential necessity of an endodontic treatment for the residual roots, the becoming of these same roots, and finally the bony and mucosal cicatrization of the operated area. Conclusion: Every oral surgeon should have in mind this technique of coronectomy and master it. Indeed, when the case justifies it, the benefits are numerous for the patient.
Interactions between leaf-cutter ants and fungus garden: Effects of division of labor, age polyethism, and egg cannibalism
Authors: Rodriguez Rodriguez Marisabel , Smith Nathan , Phan Tin , Woodbury Jonathan , Kang Yun
Published: June 2018

Division of labor (DOL), age polyethism, and egg cannibalism all play roles in shaping colony-level population dynamics in social insect colonies. The ways in which these mechanisms interact with one another to shape population dynamics is not currently understood. In this study, we examine how these mechanisms influence population dynamics in colonies of fungus-gardening leaf-cutter ants by developing and studying two sets of models: (1) We study age polyethism contribution to the dynamics of this multi-species interaction model which incorporates mechanisms of DOL; (2) We explore effects of egg cannibalism in colony dynamics and understand how to model such social conflict behavior realistically using different functional responses. Our results suggest that: (a) Age polyethism is important to keep stable population dynamics. (b) Large maturation rate and mortality rate of inside workers induce colony death. (c) Small enough egg cannibalism rate benefits adult worker ant’s growth and (or) development, large proportion of ants performing a given task can promote colony survival, and too large egg cannibalism rate can lead to colony’s death. (d) Increasing energy invested on brood care and (or) the conversion rate between fungus and ants could induce oscillatory dynamics in models with cannibalism.
Bleeding Time and Platelet Volume in Acute Myocardial Infarction – A 2 Year Follow-Up Study
Authors: Kristensen S Dalby , Milner P C , Martin J F
Published: June 2018

The bleeding time is shortened and the mean platelet volume is increased in the acute phase of myocardial infarction. In this follow-up study we repeated the measurement of the bleeding time, the platelet count and the platelet volume distribution in 18 patients who had suffered from a definite acute myocardial infarction two years before and in 16 control patients who had been admitted with chest pain but no definite myocardial infarction at that time. At the time of follow-up the bleeding time was significantly lengthened in the myocardial infarction group (median values = 169 s and 209 s respectively), whereas it had shortened in the control group (median values = 258 s and 228 s respectively). Comparison of the platelet volume distribution curves of the myocardial infarction patients at time of infarction and 2 years later revealed a significantly higher percentage of small platelets and significantly lower percentages of both medium-sized and large platelets at the time of infarction. These changes in the platelet volume distribution could indicate consumption of medium-sized and large platelets at the time of myocardial infarction. None of the measured variables predicted which of the patients with acute myocardial infarction would subsequently re-infarct or die. In the patients studied with definite ischaemic heart disease (n = 26) a significant negative correlation between bleeding time and mean platelet volume was found. The shortened bleeding time in myocardial infarction is related to the acute event itself or preceeds it, but is reversed two years later.
Immunopurification of Human Factor VIII/vWF Complex from Plasma
Authors: Mejan Odile , Fert Vincent , Delezay Maryléne , Delaage Michel , Cheballah Rose , Bourgois Alain
Published: June 2018

In this study we describe a process for immunopurification of FVIII/vWF complex directly from plasma. A mAb against vWF has been selected that is able to bind, under physiologic conditions, the FVIII/vWF complex and to release it in slightly alkaline conditions while preserving its activity.

After investigating the influence of solid supports and of coupling methods on the recovery of active FVIII we produced an immunoadsorbent by immobilisation of the selected mAb onto a Sephacryl S-1000 support using a benzoquinone coupling method. With this immunoadsorbent we developed a purification process directly from plasma with an excellent recovery (50%) of both FVIII and vWF activities. The product obtained is very enriched (the FVIII: C specific activity is 20 IU/mg of protein) and is stable after lyophilization.
Fibrinolytic and Anticoagulant Activity After a Single Subcutaneous Administration of a Low Dose of Heparin or a Low Molecular Weight Heparin-Dihydroergotamine Combination
Authors: Grimaudo V , Omri A , Kruithof E K O , Hauert J , Bachmann F
Published: June 2018

The anticoagulant and potential profibrinolytic effect of a combination of low molecular weight heparin with dihydroergotamine (LMWH-DHE) and of unfractionated heparin was studied in eight healthy volunteers. Each volunteer received a subcutaneous injection of either LMWH-DHE (1,500 U anti-Xa of LMWH + 0.5 mg DHE), unfractionated heparin (5,000 IU) or of placebo (saline) between 7 and 8 h in the morning on three different occasions. Anti-Xa activity, and fibrinolytic activity measured by the euglobulin clot lysis time (ECLT) and by the fibrin plate assay were determined before and at different times after administration of the three substances. Anti-Xa activity in plasma reached a maximum four hours after injection of both LMWH-DHE and unfractionated heparin. LMWH-DHE showed a better bioavailability when compared to unfractionated heparin; the anti-Xa activity peak was two and a half fold higher after LMWH-DHE despite injection of a three fold lower dose of anti-Xa units. The half-life of anti-Xa activity was approximately 4 hours for LMWH-DHE but only 90 min for unfractionated heparin. The fibrinolytic activity measured by ECLT as well as by fibrin plate assay, showed a significant increase during the day reaching a peak 8–12 h after injection regardless of the product administered (including the placebo). The profile of the diurnal fibrinolytic activity curve was identical for all three substances. The increase in fibrinolytic activity, observed after administration of LMWH-DHE or unfractionated heparin, was therefore not due to these drugs but reflected the circadian physiological fluctuation of fibrinolysis.
Modification of Human Thrombin: Effect on Thrombomodulin Binding
Authors: Thompson E Anne , Salem Hatem H
Published: June 2018

Thrombomodulin, an endothelial cell protein, binds thrombin with high affinity and alters thrombin from a procoagulant to an anticoagulant molecule. In this study, chemical and/or proteolytic modification of thrombin was carried out to identify the essential components required for its interaction with thrombomodulin.

Modification of thrombin at the catalytic site serine and histidine residues, with Diisopropylfluorophosphate and Tosyl-Llysine chloromethyl ketone, resulted in loss of clotting and amidolytic activity. Both Diisopropyl phosphoryl-thrombin and Tosyl-L-chloromethyl ketone-thrombin inhibited native-thrombin: thrombomodulin catalyzed protein C activation with Ki values of 5 nM and 6 nM respectively indicating no loss of affinity for thrombomodulin.

Oxidation of tryptophan residues with N-bromosuccinimide or iodination of tyrosine residues of thrombin led to reduced clotting and amidolytic activity as well as a reduced ability to interact with thrombomodulin. Modification of arginine residues with Phenylglyoxal and 2,3,Butanedione led to loss of thrombomodulin binding affinity. Limited proteolysis of thrombin by trypsin yielded the derivative β-thrombin which had also lost its ability to interact with thrombomodulin. Deglycosylation of thrombin did not alter its binding affinity for thrombomodulin.

These results indicate that one or more tryptophan, arginine and tyrosine residues are essential for the recognition of thrombin by thrombomodulin whilst the carbohydrate side chain and the active site residues of the thrombin molecule are not involved in thrombomodulin binding.
Mechanism of Rabbit Platelet Agglutination Induced by Acidic Mucopolysaccharide Extracted from Stichopus japonicus Selenka
Authors: Li Jia-Zeng , Lian Eric Chun-Yet
Published: June 2018

The effects of acidic mucopolysaccharide extracted from sea cucumber (Stichopus japonicus Selenka) (SJAMP) on rabbit platelets were studied. Using citrated platelet-rich plasma (PRP), washed platelets, and formaldehyde fixed platelets from 10 New Zealand white rabbits, we investigated the effects of platelet inhibitors and various plasma and its fractions on SJAMP-induced agglutination. It was found that the tracing of platelet agglutination induced by SJAMP showed a single phase without a lag period. The lowest concentration of SJAMP required for the agglutination of rabbit platelets was approximately 2 μg/ml, and the magnitude of agglutination induced by SJAMP was concentration dependent. In 8 out of 10 rabbits, the platelets in PRP were agglutinated by 10 μg/ml of SJAMP. Platelet inhibitors, such as aspirin, indomethacin, apyrase, antimycin, 2-deoxy-D-glucose and EDTA did not inhibit the agglutination induced by SJAMP. Washed rabbit platelets were not agglutinated by SJAMP even though the concentration of SJAMP was raised up to 50 μg/ml. When rabbit plasma, serum, or 50–60% ammonium sulfate saturated plasma fraction was added to the reaction mixture, agglutination of washed platelets by SJAMP was recovered completely. But human plasma or fibrinogen did not have any effect on the reactivity of washed rabbit platelets to SJAMP. From these data we conclude that the SJAMP-induced rabbit platelet agglutination is independent of energy metabolism but requires plasma cofactor(s) other than fibrinogen. The plasma cofactor is present in 50–60% ammonium sulfate saturated plasma fraction.
Standardization of Protein C in Plasma: Establishment of an International Standard
Authors: Hubbard A R
Published: June 2018

An international collaborative study, involving 18 laboratories, was carried out to establish an international standard for protein C in plasma. The proposed standard, which consisted of a freeze-dried ampouled plasma preparation coded 86/622, was assayed against fresh normal plasma and the participants’ local standards. Protein C activity assays were placed in four groups, depending on the method of activation and detection of protein C. The combined potencies (units per ampoule) for the proposed international standard were: thrombin activation/clottirg assays, 0.86; thrombin activation/chromogenic assays, 0.81; snake venom activation/clotting assays, 0.81 and snake venom activation/chromogenic assays, 0.82. Measurement of protein C antigen gave potency estimates of 0.81 and 0.82 units per ampoule for the Laurell electroimmunoassay and ELISA techniques, respectively. The good agreement in potency estimates between the different methods indicates that the overall combined figure (226 assays) for the international standard of 0.82 international units per ampoule should serve for all methods. Accelerated degradation studies have indicated that the standard should be suitably stable when stored at −20° C.

The freeze-dried plasma 86/622 has been established by the WHO Expert Committee on Biological Standardization as the 1st International Standard for Protein C in Plasma, with an assigned unitage of 0.82 international units per ampoule.
Uptake and Degradation of Tissue Plasminogen Activator in Rat Liver
Authors: Einarsson Monica , Smedsrød Bård , Pertoft Håkan
Published: June 2018

The mechanism of uptake of tissue plasminogen activator (tPA) in rat liver was studied. Radio-iodinated tPA was removed from the circulation after intravenous administration in a biphasic mode. The initial half life, t1/2(α), and the terminal phase, t1/2(β), were determined to be 0.5 min and 7.5 min, resp. Separation of the liver cells by collagenase perfusion and density centrifugation, revealed that the uptake per cell was two to three times higher in the non-parenchymal cells than in the parenchymal cells.

Endocytosis of fluorescein isothiocyanate-labelled or 125I-labelled tPA was studied in pure cultures of liver cells in vitro. Liver endothelial cells and parenchymal cells took up and degraded tPA. Endocytosis was more efficient in liver endothelial cells than in parenchymal cells, and was almost absent in Kupffer cells.

Competitivb inhibition experiments showing that excess unlabelled tPA could compete with the uptake and degradation of 125I-tPA, suggested that liver endothelial cells and parenchymal cells interact with the activator in a specific manner. Endocytosis of trace amounts of 125I-tPA in cultures of liver endothelial cells and parenchymal cells was inhibited by 50% in the presence of 19 nM unlabelled tPA. Agents that interfere with one or several steps of the endocytic machinery inhibited uptake and degradation of 125I-tPA in both cell types.

These findings suggest that 1) liver endothelial cells and parenchymal cells are responsible for the rapid hepatic clearance of intravenously administered tPA; 2) the activator is taken up in these cells by specific endocytosis, and 3) endocytosed tPA is transported to the lysosomes where it is degraded.
Diurnal Variation of the Fibrinolytic System
Authors: Grimaudo V , Hauert J , Bachmahh F , Kruithof E K O
Published: June 2018

To elucidate which component(s) of thei fibrinolytic system is (are) responsible for the diurnal variation of fibrinolytic activity we have studied several parameters of this system in 8 healthy male volunteers during a period of. 24 h. Blood was collected at 8 a. m., 10 a. m., 12 a. m., 4 p.m., 8 p.m. and 8 a. m. next morning. The following tests were performed: euglobulin clot lysis time (ECLT), fibrinolytic activity of euglobulins on fibrin plates in the presence and absence of blocking antibodies to tissue-type plasminogen activator (t-PA) and/or urokinase (u-PA), overall plasminogen activator inhibitor (PAI) activity, antigen levels of t-PA, u-PA and PAI-I and zymography of the euglobulin fraction after SDS-PAGE. From 8-10 a. m. to 4-8 p. m., total fibrinolytic activity increased by 1l3% (p <0.01) or 71%h (p <0.01) when measured by ECIX or by fibrin plate assay, respectively. The immunoquenching experiments showed that this increase was entirely due to t-PA related activity whereas u-PA activity and t-PA/u-PA independent activity remained constant during the day. Average antigen levels of u-PA and t-PA in the afternoon were 6% and 25% lower than those measured in the morning. During this period, overall PAI activity and PAI-1 antigen decreased by 3l% (p <0.01) and 52% (p <0.01) respectively. Electrophoretic-zymographic analysis of_ the euglobulins revealed that throughout the day the majority of t-PA was present in the form of the 110 kDa t-PA/PAI-I complex. The intensity of this cornplex was lowest in the afternoon. Free t-PA was almost undetectable in morning samples, but constituted a significant proportion of total t-PA in the afternoon. The diurnal increase of fibrinolytic activity, therefore, is not due to an augmentation of antigen levels of t-PA and/or u-PA but to a decline of those of PAI-1.
Clinically Mild Thrombasthenia with Normal Platelet Coagulant Activities
Authors: Walsh P. N , Rizza C. R , McLennan R
Published: June 2018

The results of assaying platelet coagulant activities in a patient with clinically mild thrombasthenia are compared with those previously reported in 4 patients with clinically severe and 2 patients with moderately severe thrombasthenia. Contact product forming activity and platelet factor 3 activity were normal in the present patient, and decreased in the more severely affected patients. Intrinsic factor-Xa forming activity was normal or supranormal in all patients. Collagen-induced coagulant activity was present in mildly and moderately affected patients and absent in severely affected patients. The present patient would appear to possess both alternative mechanisms by which platelets can initiate intrinsic clotting, compared to the moderately affected patients who lack one and the severely affected patients who lack both pathways. Although the present patient’s platelets failed to aggregate in response to ADP they responded normally to ADP in the assay for contact product forming activity.
Studies on the Activation of Human Factor XIII
Authors: Sheltawy Marion J. , Miloszewski Krzysztof , Losowsky Monty S.
Published: June 2018

Studies on antithrombin levels of heat-treated plasma showed that thrombin is rapidly removed during the first five minutes of incubation and thereafter removed more slowly until a plateau is reached at 25 minutes when about 20% of the thrombin remained regardless of the initial amount.

The calcium requirements of thrombin activation were studied by using thrombin in insoluble form bound to Sepharose - 4B. Calcium ions were not essential for activation of factor XIII in plasma or purified factor XIII. With purified factor XIII calcium ions decreased activation, whereas with plasma factor XIII calcium ions increased activation.

Activation of plasma factor XIII can be accomplished by Reptilase or trypsin as well as thrombin, when activity is measured by the ability to stabilise fibrin. When measured by the dansyl cadaverine method, only Reptilase and thrombin activate factor XIII. Arvin did not activate factor XIII and formed an unstable clot.
The Effects of Brinolase (Fibrinolytic Enzyme from Aspergillus Oryzae) on Platelet Aggregation of Dog and Man
Authors: Roschlau W. H. E , Gage R
Published: June 2018

Inhibition of blood platelet aggregation by brinolase (fibrinolytic enzyme from Aspergillus oryzae) has been demonstrated with human platelets in vitro and with dog platelets in vivo and in vitro, using both ADP and collagen as aggregating stimuli. It is suggested that the optimal inhibitory effects of brinolase occur indirectly through the generation of plasma fibrinogen degradation products, without compromising platelet viability, rather than by direct proteolysis of platelet structures.
Evaluation of the Fibrin Plate Method for Estimating Plasminogen Activators
Authors: Marsh N. A , Arocha-Pinango C. L
Published: June 2018

A study was carried out in order to evaluate the Astrup and Mullertz fibrin plate method for estimating plasminogen activators.

Choice of a suitable fibrinogen substrate was found to be the most important factor in setting up a workable assay. Many preparations contained a large proportion of non-clottable protein and plates made from these fibrinogens were usually unreliable. In addition, plasminogen content varied appreciably between preparations so that sensitivity of the method required careful calibration with each new batch of fibrinogen.

The effect of additives in the fibrin plate was considered and it was found that calcium chloride alone was sufficient to ensure a stabilised plate which could be stored at 4° C for some time. The addition of tranexamic acid (AMCHA) was found to be a slightly more convenient way of estimating direct proteolytic activity, compared with the traditional heated plate. However neither method distinguished completely between proteolysis and plasminogen activation.

In order to improve the precision of the method, the use of an analysis of variance technique has been studied. This technique provides information on the dose-response curves of test and unknown substances, and in addition produces an approximately threefold increase in precision over single plate tests.
The Treatment of Patients Having Spontaneously Occurring Antibodies to Antihaemophilic Factor (Factor VIII)
Authors: Rizza C.R , Edgcumbe J.O.P , Pitney W.R , Child J.A
Published: June 2018

The appearance of antibodies to factor VIII in the blood of previously normal people is a very rare occurrence but when it does happen the haemorrhagic condition which results can be very serious and difficult to treat.

From experience of three cases described here it is recommended that treatment be witheld unless there is serious haemorrhage in which case steroids, large doses of cryoprecipitate or other human AHG should be given. In the case of life endangering haemorrhages it is justified to use the much more potent animal AHG preparations along with an immuno-suppressive drug.
Oral Contraceptives and Platelet Function
Authors: Mettler L , Selchow Meseck B.
Published: June 2018

Platelet function was studied in women receiving two oral oestrogen-progestagen compounds (Neogynon and Noracyclin-22). Platelet count, adhesiveness, spreading, aggregation (PAT) and thromboelastography (TEG) were studied twice monthly for six months in 186 cycles. Platelet counts in rotated plasma were decreased in both groups. A significant increase in non-spread platelets was found in the Neogynon group only. PAT-degrees were significantly increased in both groups. Platelet adhesiveness and thromboelastographic measurements were not affected. Increased platelet aggregation during oral contraceptive therapy is regarded as a predisposing factor to thrombosis.
The Effect of Neuraminidase on Platelet Aggregation Induced by ADP, Norepinephrine, Collagen or Serotonin
Authors: Davis James W. , Yue Kenneth T. N. , Phillips Phyllis E.
Published: June 2018

Incubation of human platelet-rich plasma (PRP) with neuraminidase enhanced platelet aggregation induced by adenosine diphosphate (ADP), norepinephrine, collagen or serotonin. Both first and second phases of ADP- and norepinephrine -induced aggregation were enhanced. In two plasmas a second phase of ADP-induced aggregation occurred after incubation with neuraminidase, but not in the control preparations. In one plasma a second phase of serotonin-induced platelet aggregation occurred after incubation with neuraminidase. The incubation of PRP with exogenous N-acetylneuraminic acid (a product of the action of neuraminidase) had no effect on platelet aggregation. A possible explanation of the observed enhancement of platelet aggregation by neuraminidase is that the enzyme may have released sialic acid from platelet membranes and thereby reduced their net negative surface charge.
Factor VIII International Units and Reference Materials
Authors: Bangham Derek R , Brozović Milica
Published: June 2018

The establishment of the International Standard for factor VIII has introduced a common yardstick, the international unit, which all countries can apply. This standard is a concentrate of intermediate purity, shown to be very stable on long term storage. As with all international standards it is available in limited quantities and is primarily used for the calibration of national standards used to monitor patients and in the control of therapeutic preparations.

Since 1969 in Great Britain such a national standard has been made from freeze-dried pooled plasma. This has been available in larger quantities and has been introduced into routine use in coagulation laboratories. As factor VIII in freeze-dried plasma has limited stability even when stored at —20° C, successive new batches are prepared every two years or so. The availability of a common working standard with factor VIII content specified in international units makes it possible to define diagnostic and therapeutic criteria with more precision than hitherto. This system can be applied in other countries and to other clotting factors for which an international yardstick is needed.
The Corrective Effect of Factor VIII-coated Red Blood Cells in Haemophilic Plasma with Antibodies to Factor VIII
Authors: Uszyński Leszek
Published: June 2018

Factor VIII-coated red blood cells had an evident corrective effect on plasma of haemophiliacs with inhibitors. This effect was especially significant when tanned coated red cells were used. The direct coating of washed red blood cells by factor VIII concentrates is also feasible. The results were better with fraction C-I (AHG concentrate containing dextran) than with fibrinogen-free concentrate. It seems that dextran enhances the attachment of factor VIII to human erythrocytes. In the direct coating-procedure the time of incubation was important, but temperature and pH were not critical. The results obtained indicate that factor VIII attached to red blood cells is more resistant to inhibitors than factor VIII in solution.

The possibility of using factor VIII-coated red cells for the management of patients with antibodies to factor VIII is discussed.
The Effect of Major Surgical Procedures on Plasma and Platelet Levels of Factor XIII
Authors: Letheby Beth A , Davis Richard B , Larsen Arden E
Published: June 2018

Factor XIII (FSF or fibrinoligase), an enzyme required for normal blood coagulation, can be measured by its catalysis of the incorporation of a fluorescent amine, monodansylcadaverine (N-(5-aminopentyl)-5-dimethylamino-l-naphthalene-sulfon-amide) into casein. The amine incorporation test was applied to fourteen patients who had major operations. Levels of factor XIII were measured before surgery and at intervals of two, four, and six days after operation. Plasma factor XIII showed a significant, linear decrease for each day after surgery. Patients having orthopedic surgery showed less pronounced changes than the remaining patients. Factor XIII also decreased after operation in patients with neoplastic disease, but the change was not different from that after general surgical procedures done in the absence of neoplasia. Platelet factor XIII levels were increased on the second day after operation, diminished on day four, and increased above pre-operative levels on the sixth day after surgery. Possible explanations of the observations are presented.
A Direct Enzymatic Assay for the Esterolytic Activity of Activated Hageman Factor
Authors: Ulevitch Richard J , Letchford David , Cochrane C. G
Published: June 2018

A direct enzymatic assay for activated Hageman factor (HFa) has been developed utilizing N-α-acetylgiycine lysine methyl ester (AGLME). This assay allowed the measurement of the esterolytic activity of purified Hageman factor (HF) which had been activated by enzymatic (trypsin) and non-enzymatic (kaolin) mechanisms. No esterolytic activity was detected in preparations of purified HF prior to activation.

Studies with purified HF activated on kaolin demonstrated the following: (1) Simple saturation kinetics (Km = 9 mM, Turnover number = 2.5 min–1) at AGLME concentrations less than 0.04 M and substrate inhibition at AGLME concentrations greater than 0.04 M. (2) The substrate AGLME behaved as a competitive inhibitor of the activation of prekallikrein (PK) by HFa with an inhibition constant (Ki) of about 10 mM. (3) Both the esterolytic (AGLME hydrolysis) and the proteolytic activities (PK activation) were inhibited by diisopropylfluorosphosphate (DFP) with an approximate Ki of 5 × 10–4 M.
Isolation and Characterization of Plasminogen Activator from Pig Leucocytes
Authors: Kopitar M , Stegnar M , Accetto B , Lebez D
Published: June 2018

Plasminogen activator was isolated from disrupted pig leucocytes by the aid of DEAE chromatography, gel filtration on Sephadex G-100 and final purification on CM cellulose, or by preparative gel electrophoresis.

Isolated plasminogen activator corresponds No. 3 band of the starting sample of leucocyte cells (that is composed from 10 gel electrophoretic bands).

pH optimum was found to be in pH range 8.0–8.5 and the highest pH stability is between pH range 5.0–8.0.

Inhibition studies of isolated plasminogen activator were performed with EACA, AMCHA, PAMBA and Trasylol, using Anson and Astrup method. By Astrup method 100% inhibition was found with EACA and Trasylol and 30% with AMCHA. PAMBA gave 60% inhibition already at concentration 10–3 M/ml. Molecular weight of plasminogen activator was determined by gel filtration on Sephadex G-100. The value obtained from 4 different samples was found to be 28000–30500.
The Relationship between Platelet Aggregation and Time Interval after Venepuncture
Authors: Warlow Charles , Corina Anne , Ogston D , Douglas A. S
Published: June 2018

The relationship between the rate of platelet aggregation and the time interval after venepuncture has been studied. Considerable changes in the rates of aggregation and disaggregation of platelets in citrated plasma take place between 30 and 120 minutes after venepuncture. There is a reduction in the rates of irreversible ADP-induced aggregation, the first and second phase of the double wave of ADP-induced aggregation, disaggregation after reversible ADP-induced aggregation, collagen-induced aggregation and the second phase of the double wave of adrenaline-induced aggregation. In contrast, the rate of the first wave of adrenaline-induced aggregation increases with time after venepuncture. 5-HT induced aggregation appears to be unaffected. These effects were not due to changes in the pH of the plasma. It is suggested that any attempt to quantify platelet aggregation during the comparison of groups of individuals, or in the study of the effect of anti-platelet drugs in single individuals must take into account the time interval between venepuncture and the measurement of platelet aggregation.
Studies on the Shape Change in Rabbit Platelets Induced by Adenosine Diphosphate or Several Metabolic Inhibitors
Authors: Kobayashi Norio , Maekawa Tadashi
Published: June 2018

1. The shape change of platelet was induced in vitro by an addition of ADP, NEM, KCN or distilled water. The change induced by ADP occurred very rapidly.

2. Among these reagents, only ADP induced the platelet aggregation.

3. When ADP was added before the completion of the shape change by NEM, the shape change by ADP took place, while both ADP and NEM were added simultaneously, the pattern of the shape change was similar to that of ADP alone.

4. The shape change of platelet by ADP was inhibited by the previous addition of adenosine, which did not affect the shape change induced by NEM.

5. Correlation of the shape change of platelets to their aggregation was discussed.
Arterial and Venous Thromboembolism: Kinetic Characterization and Evaluation of Therapy
Authors: Harker Laurence A , Slichter Sherrill J
Published: June 2018

Survival and turnover measurements of platelets, fibrinogen and plasminogen have been studied in eight patients with arterial and twelve patients with venous thromboembolism, and six patients with advanced, stable atherosclerotic peripheral vascular disease.

Venous thrombosis is characterized by combined and equivalent consumption of platelets, fibrinogen and plasminogen. This process, the result of activation of the coagulation system, is completely reversed by heparin or warfarin anticoagulation but remains unaltered by dipyridamole. The removal of circulating plasminogen is directly reflected as fibrinogen-fibrin related antigen in the blood and is regulated by the rate of fibrin formation as evidenced by the reversal of fibrinogen and plasminogen consumption to normal following heparin therapy.

In contrast, arterial thromboembolism involves selective platelet consumption presumably in the formation of platelet thrombus on non-endothelialized end-arterial surfaces. This process is interrupted by dipyridamole inhibition of platelet function but not by heparin anticoagulation. Although acetylsalicylic acid itself has little capacity to correct platelet consumption, it has a potentiating effect on dipyridamole.

Stable, severe, widespread arteriosclerotic disease only minimally increases platelet consumption and produces no change in fibrinogen and plasminogen kinetics from normal. The minimal decrease in platelet survival in these patients is not corrected by dipyridamole therapy.

The results of these studies demonstrate the potential usefulness of platelet and fibrinogen kinetic measurements in the differentiation of ongoing venous and arterial thromboembolism and in identifying potentially effective antithrombotic therapy.
Platelet Electrophoresis: The Present Position
Authors: Hampton J. R , Mitchell J. R. A
Published: June 2018

Measurements of platelet aggregation and adhesion have proved disappointing in the study of individual subjects with, or at risk from, arterial disease. In this paper the technique of platelet electrophoresis is described, and it is shown that with this technique individual patients with coronary artery disease can be identified with a high degree of accuracy. Abnormal platelet electrophoretic behaviour is also described in the relatives of subjects who have had a myocardial infarction at an early age, and it is suggested that the platelet abnormality precedes clinically-detectable disease.

The platelet abnormality is shown to be secondary to changes in the plasma, and experiments are described in which a start has been made in elucidating the nature of the plasma abnormality. Two plasma components are involved: one is probably adenosine diphosphate (ADP), and it is shown that ADP has two distinct effects on platelets; the other component is associated with the plasma low-density lipoproteins.

The nature of the low-density lipoprotein abnormality that induces platelet changes that can be detected by this electrophoretic technique appear of extreme importance in the understanding of thrombosis. No specific chemical abnormality has been identified in these lipoproteins, but certain detergents are shown to have a similar effect on platelet electrophoretic behaviour. It is therefore suggested that there are changes in the surface-active, or detergent, properties of the lipoproteins in subjects with, or at risk from, arterial disease.
Causes of a Negative Ethanol Gelation Test in Diffuse Intravascular Coagulation
Authors: Gerrits W. B. J , Prakke Elisabeth M , van der Meer J , Vreeken J
Published: June 2018

The clinical value of the ethanol gelation test (EGT) in diagnosing diffuse intravascular coagulation (DIC) has been questioned because of the occasional finding of a negative test, while other laboratory data pointed to DIC. Therefore, the behaviour of the EGT during thrombin infusions in rabbits was studied, with special reference to the fibrinogen level and activation of fibrinolysis. Fibrinolytic activity was inhibited or induced by synchronous infusion of epsilon-aminocaproic acid or plasmin respectively. The results obtained show that apart from severe depletion of fibrinogen strong activation of fibrinolysis can cause a negative EGT during thrombin infusions in rabbits. This phenomenon could not be ascribed to high levels of fibrin degradation products (fdp); it might be due to plasmin digestion of fibrin monomers. In vitro studies with human plasma confirmed that the EGT becomes negative at a fibrinogen level of less than 20 mg per 100 ml or by plasmin activity in the presence of a normal fibrinogen level.

Whereas a positive EGT is highly specific for DIC, these studies show that a negative EGT does not exclude the presence of DIC.
Blood Coagulation and Platelet-function Parameters before and during Parenteral Administration of Medroxyprogesterone Acetate as a Contraceptive Agent
Authors: Baele G , Vermeulen A , Thiery M
Published: June 2018

The effects of medroxyprogesterone acetate on blood coagulation and platelet collagen aggregation were studied in nineteen women. After parenteral administration of the compound for 4 and 7 months, the activated partial thromboplastin time showed a significant decrease. The percentage of the prothrombin time test rose after 4 months, but not significantly after 7 months ; factor II decreased after 7 months of treatment. The reaction time during which no aggregation occurred after addition of a collagen suspension to a stirred platelet-rich plasma, was shorter after both 4 and 7 months of treatment. Other coagulation and platelet-function parameters were not altered. Although a trend toward hypercoagulability was detected, the changes were not the same as those reported for combined oral contraceptives.