The Role of Calcium on the Release of Tissue Factor (Thromboplastie) Activity from Leukocytes

1975 ◽  
Author(s):  
T. W. Muhlfelder ◽  
I. Khan ◽  
J. Niemetz
Keyword(s):  
Tissue Factor ◽  
Maximum Activity ◽  
Release Mechanism ◽  
Temperature Dependent ◽  
Cell Contractility ◽  
Thromboplastic Activity ◽  
Significant Release ◽  
Ca Ions ◽  
The One

It is now well established that leukocytes may generate tissue factor (thromboplastic) activity (TFa), particularly after “stimulation” with endotoxin. As these leukocytes have also a thrombogenic effect, it appeared desirable to study the conditions in which the TFa was released. Leukocytes were obtained from the peritoneal cavity of rabbits after 2 doses of endotoxin and prepared as described previously (Nature New Biol. 232, 247, 1971). The leukocytes were incubated in siotonic buffered solutions, for up to 30 min then sedimented by centrifugation and the supemate removed for testing. The TFa was tested by the one stage test and the 2 stage assay. Significant release of procoagulant activity occured only when the leukocytes were suspended in solutions containing calcium. 2 mM of calcium caused maximum release of TFa while lower or higher concentrations were less effective. Other bivalent cations (Mg, Mn Zn) could not replace Ca ions and caused no release, while Co caused only very slight release of TFa. The release was time and temperature dependent: maximum activity being released at 37°C and almost no activity released at 4° C. When the effect of pH was studied, maximum release of TFa occurcd at pH 6.5–7.5. Substances which affect cell contractility such as vincristine, colchicine, cytochalasin B, as well as ouabain which affects some ATPase’s had no effect on release. These data show tlrat leukocyte tissue factor activity can be released from the cell in the presence of calcium. This release mechanism may play a role in some pathological conditions.(Supported in part by NIH Grant 13155 and VA 6060–01.)

Mesoscopic free energy as a framework for modeling shape memory alloys

2019 ◽  
Vol 30 (13) ◽  
pp. 1969-2012
Author(s):  
Wesley Ballew ◽  
Stefan Seelecke
Keyword(s):  
Free Energy ◽  
Shape Memory ◽  
Latent Heat ◽  
Compressive Behavior ◽  
Temperature Dependent ◽  
One Dimensional ◽  
Dimensional Shape ◽  
The Difference ◽  
The One

This article presents a reinterpretation of the one-dimensional shape memory alloy model by Müller, Achenbach, and Seelecke (M-A-S) that offers extended capabilities and a simpler formulation. The cornerstone of this model is a continuous, multi-well free energy that governs phase change at a mesoscopic material scale. The free energy has been reformulated to allow asymmetric tensile and compressive behavior as well as temperature-dependent hysteresis while maintaining the necessary smoothness conditions. The free energy is then used to derive expressions for latent heat coefficients that include the influence of stress, the difference in stiffness between the phases, and irreversibility. Special attention is devoted to the role of irreversibility and latent heat predictions, which are compared to experimental measurements. The new model also includes an updated set of kinetics equations that operate on the convexity of the energy wells instead of the height of the energy barriers. This modification eliminates several sets of equations from the overall formulation without any compromises in performance and also bypasses limitations of the barrier-based equations.

scholarly journals Tissue-factor coagulant activity of cultured human endothelial and smooth muscle cells and fibroblasts

Blood ◽  
1977 ◽  
Vol 50 (3) ◽  
pp. 387-396 ◽  
Author(s):  
JR Maynard ◽  
BE Dreyer ◽  
MB Stemerman ◽  
FA Pitlick
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Tissue Factor ◽  
Time Course ◽  
Peak Level ◽  
Cell Types ◽  
Maximum Activity ◽  
Cell Tissue ◽  
Thromboplastic Activity ◽  
High Level

The tissue-factor (thromboplastic) activity of cultured human endothelial cells and fibroblasts is low at time of transfer into fresh medium but increases 3–10 fold. Endothelial cells reach peak activity (400 U/10(5) cells) 5–8 hr after subculture. Activity in fibroblast cultures peaks (3000–12,000 U/10(5) cells) 7–12 hr after subculture. After attaining maximum activity, endothelial and fibroblast tissue- factor content decreases in a time course similar to other cells studied in this laboratory, approaching basal levels by 24–50 hr after subculture. If medium over fibroblasts is changed every 12 hr, activity can be sustained at the peak level for an additional day but cannot be maintained at a high level indefinitely. The kinetics of expression of smooth muscle cell tissue factor are markedly different from other cell types. There is always a pronounced lag (30 hr or more) before the activity increases, and then, in most cases, there is no subsequent decline in activity even though the cells are not refed or restimulated. The activity of each of these cell types is cryptic but becomes available after freeze-thaw disruption of cells.

Tissue-factor coagulant activity of cultured human endothelial and smooth muscle cells and fibroblasts

Blood ◽  
1977 ◽  
Vol 50 (3) ◽  
pp. 387-396 ◽  
Author(s):  
JR Maynard ◽  
BE Dreyer ◽  
MB Stemerman ◽  
FA Pitlick
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Tissue Factor ◽  
Time Course ◽  
Peak Level ◽  
Cell Types ◽  
Maximum Activity ◽  
Cell Tissue ◽  
Thromboplastic Activity ◽  
High Level

Abstract The tissue-factor (thromboplastic) activity of cultured human endothelial cells and fibroblasts is low at time of transfer into fresh medium but increases 3–10 fold. Endothelial cells reach peak activity (400 U/10(5) cells) 5–8 hr after subculture. Activity in fibroblast cultures peaks (3000–12,000 U/10(5) cells) 7–12 hr after subculture. After attaining maximum activity, endothelial and fibroblast tissue- factor content decreases in a time course similar to other cells studied in this laboratory, approaching basal levels by 24–50 hr after subculture. If medium over fibroblasts is changed every 12 hr, activity can be sustained at the peak level for an additional day but cannot be maintained at a high level indefinitely. The kinetics of expression of smooth muscle cell tissue factor are markedly different from other cell types. There is always a pronounced lag (30 hr or more) before the activity increases, and then, in most cases, there is no subsequent decline in activity even though the cells are not refed or restimulated. The activity of each of these cell types is cryptic but becomes available after freeze-thaw disruption of cells.

You Are the One I Want to Communicate With!

2013 ◽  
Vol 44 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Sabrina Pierucci ◽  
Olivier Klein ◽  
Andrea Carnaghi
Keyword(s):  
Memory Bias ◽  
Shared Reality ◽  
Communication Partner ◽  
Shared Reality Theory ◽  
The One ◽  
Study Participants

This article investigates the role of relational motives in the saying-is-believing effect ( Higgins & Rholes, 1978 ). Building on shared reality theory, we expected this effect to be most likely when communicators were motivated to “get along” with the audience. In the current study, participants were asked to describe an ambiguous target to an audience who either liked or disliked the target. The audience had been previously evaluated as a desirable vs. undesirable communication partner. Only participants who communicated with a desirable audience tuned their messages to suit their audience’s attitude toward the target. In line with predictions, they also displayed an audience-congruent memory bias in later recall.

Factor Xa Enhances the Binding of Tissue Factor Pathway Inhibitor to Acidic Phospholipids

1996 ◽  
Vol 75 (05) ◽  
pp. 796-800 ◽  
Author(s):  
Sanne Valentin ◽  
Inger Schousboe
Keyword(s):  
Tissue Factor ◽  
Tissue Factor Pathway Inhibitor ◽  
Factor Xa ◽  
Microtitre Plate ◽  
C Terminus ◽  
Microtitre Plate Assay ◽  
Kunitz Domain ◽  
Tissue Factor Pathway ◽  
Acidic Phospholipids

SummaryIn the present study, the interaction between tissue factor pathway inhibitor (TFPI) and phospholipids has been characterized using a microtitre plate assay. TFPI was shown to bind calcium-independently to an acidic phospholipid surface composed of phosphatidylserine, but not a surface composed of the neutral phosphatidylcholine. The interaction was demonstrated to be dependent on the presence of the TFPI C-terminus. The presence of heparin (1 U/ml, unfractionated) was able to significantly reduce the binding of TFPI to phospholipid. The interaction of TFPI with phosphatidylserine was significantly decreased in the presence of calcium, but this was counteracted, and even enhanced, following complex formation of TFPI with factor Xa prior to incubation with the phospholipid surface. Moreover, a TFPI variant, not containing the third Kunitz domain and the C-terminus, was unable to bind to phospholipid. However, following the formation of a TFPI/factor Xa-complex this TFPI variant was capable of interacting with the phospholipid surface. This indicates that the role of factor Xa as a TFPI cofactor, at least in part, is to mediate the binding of TFPI to the phospholipid surface.

The Formation of Intermediate Product I in a Purified System The Role of Factor IX or of its Precursor and of a Hageman Factor-PTA Fraction

1961 ◽  
Vol 6 (02) ◽  
pp. 224-234 ◽  
Author(s):  
E. T Yin ◽  
F Duckert
Keyword(s):  
Intermediate Product ◽  
Factor Ix ◽  
Assay Method ◽  
Lag Phase ◽  
Factor X ◽  
Haemophilia B ◽  
Hageman Factor ◽  
One Stage ◽  
The One

Summary1. The role of two clot promoting fractions isolated from either plasma or serum is studied in a purified system for the generation of intermediate product I in which the serum is replaced by factor X and the investigated fractions.2. Optimal generation of intermediate product I is possible in the purified system utilizing fractions devoid of factor IX one-stage activity. Prothrombin and thrombin are not necessary in this system.3. The fraction containing factor IX or its precursor, no measurable activity by the one-stage assay method, controls the yield of intermediate product I. No similar fraction can be isolated from haemophilia B plasma or serum.4. The Hageman factor — PTA fraction shortens the lag phase of intermediate product I formation and has no influence on the yield. This fraction can also be prepared from haemophilia B plasma or serum.

Studies on the Pathogenesis of the Generalized Shwartzman Reaction

1964 ◽  
Vol 12 (02) ◽  
pp. 471-483 ◽  
Author(s):  
F Rodríguez-Erdmann
Keyword(s):  
Clotting Factor ◽  
Factor V ◽  
Clotting System ◽  
Platelet Factor ◽  
Trigger Mechanism ◽  
Haemorrhagic Diathesis ◽  
Shwartzman Reaction ◽  
Ca Ions

SummaryThe rôle of the clotting system in the pathogenesis of the generalized Shwartzman reaction (gSr) has been stressed in recent years. The clotting system is activated ubiquitously and as a result of it, fibrin is deposited intravascularly and a haemorrhagic diathesis develops. Evidence is presented herein, that endotoxin does not activate purified prothrombin, nor does endotoxin influence the convertion of prothrombin when it is activated in the presence of purified platelet-factor 3 (or caephalin) purified Ac-G (factor V) and Ca-ions.The trigger mechanism of the gSr also seems to be in the so-called prephase of clotting mechanism. Data are presented, which show that endotoxin activates the Hageman factor in vitro. The importance of this clotting factor and of platelet-factor 3 is discussed. Also the rôle played by the RES and cardiodynamic and vascular components are taken in consideration in the discussion.

THE ROLE OF ANTHROPONYMS IN THE SEMANTIC FIELD OF ARTISTIC WORKS

2019 ◽  
Vol 2019 (29) ◽  
pp. 66-77
Author(s):  
Lidiya Derbenyova
Keyword(s):  
Literary Work ◽  
Main Theme ◽  
Semantic Field ◽  
New Meanings ◽  
Minor Part ◽  
The One ◽  
A Minor ◽  
And Storage ◽  
Horizon Of Expectations

The article explores the role of antropoetonyms in the reader’s “horizon of expectation” formation. As a kind of “text in the text”, antropoetonyms are concentrating a large amount of information on a minor part of the text, reflecting the main theme of the work. As a “text” this class of poetonyms performs a number of functions: transmission and storage of information, generation of new meanings, the function of “cultural memory”, which explains the readers’ “horizon of expectations”. In analyzing the context of the literary work we should consider the function of antropoetonyms in vertical context (the link between artistic and other texts, and the groundwork system of culture), as well as in the context of the horizontal one (times’ connection realized in the communication chain from the word to the text; the author’s intention). In this aspect, the role of antropoetonyms in the structure of the literary text is extremely significant because antropoetonyms convey an associative nature, generating a complex mechanism of allusions. It’s an open fact that they always transmit information about the preceding text and suggest a double decoding. On the one hand, the recipient decodes this information, on the other – accepts this as a sort of hidden, “secret” sense.

Public Procurement Principles Generated by the Treaty of Rome

2020 ◽  
Vol 26 (2) ◽  
pp. 217-223
Author(s):  
Ioan-Gabriel Popa
Keyword(s):  
European Economic Community ◽  
Public Procurement ◽  
Free Movement ◽  
European Directives ◽  
Community Institutions ◽  
Treaty Of Rome ◽  
General Principles Of Law ◽  
Free Movement Of Goods ◽  
The One

AbstractIn order to understand the principles of public procurement in Romania, it is necessary to analyze, on the one hand, the European directives that regulate the actual public procurement and, on the other hand, the context in which the European directives were adopted. Even with the directives in force, the more general provisions contained in the Treaty of the European Economic Community (EEC) in Rome, hereinafter referred to as the Treaty, are applied, as well as many more general principles of law that will guide the interpretation of these directives. The Treaty was adopted in Rome, in 1957 and became applicable from January 1, 1958. It is considered that the source of the principles of public procurement is the Treaty. Even if in Treaty contained no specific provisions regarding the field of public procurement, it reflects the principles and the general framework for the functioning of the single market, a market characterized through the prism of the fundamental freedoms established by the Treaty: the free movement of goods, services, capital and persons. As the field of public procurement is closely linked to the free movement of goods, this principle is promoted and implemented in the practice of this field based on the regulations, directives and decisions of the Community institutions. The role of the free movement of goods is to harmonize the relationships involved in the process of purchasing goods, but also to ensure the homogeneity, coherence and balance of this process.

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