Effect of Temperature, Velocity Gradient and I.V. Heparin on in Vitro Blood Coagulation and Platelet Aggregation

1967 ◽  
Vol 17 (01/02) ◽  
pp. 112-119 ◽  
Author(s):  
L Dintenfass ◽  
M. C Rozenberg
Keyword(s):  
Blood Coagulation ◽  
Velocity Gradient ◽  
Elevated Temperatures ◽  
Morphological Changes ◽  
Effect Of Temperature ◽  
Clotting Time ◽  
Progressive Change ◽  
Aggregation Of Platelets ◽  
Microscopic Techniques

SummaryA study of blood coagulation was carried out by observing changes in the blood viscosity of blood coagulating in the cone-in-cone viscometer. The clots were investigated by microscopic techniques.Immediately after blood is obtained by venepuncture, viscosity of blood remains constant for a certain “latent” period. The duration of this period depends not only on the intrinsic properties of the blood sample, but also on temperature and rate of shear used during blood storage. An increase of temperature decreases the clotting time ; also, an increase in the rate of shear decreases the clotting time.It is confirmed that morphological changes take place in blood coagula as a function of the velocity gradient at which such coagulation takes place. There is a progressive change from the red clot to white thrombus as the rates of shear increase. Aggregation of platelets increases as the rate of shear increases.This pattern is maintained with changes of temperature, although aggregation of platelets appears to be increased at elevated temperatures.Intravenously added heparin affects the clotting time and the aggregation of platelets in in vitro coagulation.

scholarly journals Role of Serotonin in Blood Coagulation

1957 ◽  
Vol 189 (3) ◽  
pp. 470-474 ◽  
Author(s):  
W. L. Milne ◽  
S. H. Cohn
Keyword(s):  
Blood Coagulation ◽  
Therapeutic Effect ◽  
Whole Blood ◽  
Active Role ◽  
Clotting Time ◽  
Platelet Factor ◽  
Coagulation Defect ◽  
Increased Sensitivity

Effects of serotonin (5HTA) were studied a) in whole blood ( in vitro) from both normal and x-irradiated animal, and b) in isolated clotting systems of plasma and purified fibrinogen. 5HTA was found to play an active role in blood coagulation in addition to its previously demonstrated role as a vasoconstrictor. In whole blood from normal and irradiated animals, and in platelet-deficient plasma, 5HTA acts in a manner similar to platelet factor 2 in accelerating the conversion of fibrinogen to fibrin. In a purified fibrinogen solution, 5HTA inhibits the fibrinogen-fibrin reaction, and thus differs from platelet factor 2. This may be due to the absence of an antithrombin in the purified fibrinogen solution. Serotonin appears to have a therapeutic effect on the postirradiation coagulation defect in that it decreases the prolonged heparin clotting time. This increased sensitivity to heparin during the postirradiation thrombocytopenia may be due to a deficiency of serotonin, which acts as an antagonist to heparin (an antithrombin). The action of 5HTA is postulated as an antagonist of an antithrombin which blocks the fibrinogen to fibrin reaction.

Antiplatelet agents in tissue factor–induced blood coagulation

Blood ◽  
2001 ◽  
Vol 97 (8) ◽  
pp. 2314-2322 ◽  
Author(s):  
Saulius Butenas ◽  
Kevin M. Cawthern ◽  
Cornelis van't Veer ◽  
Maria E. DiLorenzo ◽  
Jennifer B. Lock ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Blood Coagulation ◽  
Platelet Activation ◽  
Whole Blood ◽  
Antiplatelet Agents ◽  
Receptor Activation ◽  
Clotting Time ◽  
Ligand Interaction ◽  
Clot Time

Abstract Several platelet inhibitors were examined in a tissue factor (TF)–initiated model of whole blood coagulation. In vitro coagulation of human blood from normal donors was initiated by 25 pM TF while contact pathway coagulation was suppressed using corn trypsin inhibitor. Products of the reaction were analyzed by immunoassay. Preactivation of platelets with the thrombin receptor activation peptide did not influence significantly the clotting time or thrombin–antithrombin III complex (TAT) formation. Addition of prostaglandin E1 (5 μM) caused a significant delay in clotting (10.0 minutes) versus control (4.3 minutes). The prolonged clotting time is correlated with delays in platelet activation, formation of TAT, and fibrinopeptide A (FPA) release. In blood from subjects receiving acetylsalicylic acid (ASA or aspirin), none of the measured products of coagulation were significantly affected. Similarly, no significant effect was observed when 5 μM dipyridamole (Persantine) was added to the blood. Antagonists of the platelet integrin receptor glycoprotein (gp) IIb/IIIa had intermediate effects on the reaction. A 1- to 2-minute delay in clot time and FPA formation was observed with addition of the antibodies 7E3 and Reopro (abciximab) (10 μg/mL), accompanied by a 40% to 70% reduction in the maximal rate of TAT formation and delay in platelet activation. The cyclic heptapetide, Integrilin (eptifibatide), at 5 μM concentration slightly prolonged clot time and significantly attenuated the maximum rate of TAT formation. The disruption of the gpIIb/IIIa-ligand interaction not only affects platelet aggregation, but also decreases the rate of TF-initiated thrombin generation in whole blood, demonstrating a potent antithrombotic effect superimposed on the antiaggregation characteristics.

Effect of i. v. and Oral Administration of Heparinoids G31150, G31150-A and of Nitrilotriacetic Acid on Blood Coagulation

1971 ◽  
Vol 25 (01) ◽  
pp. 187-200 ◽  
Author(s):  
C. L Jarrett ◽  
L. B Jaques
Keyword(s):  
Absorption Spectrum ◽  
Oral Administration ◽  
Blood Coagulation ◽  
Intravenous Injection ◽  
Anticoagulant Activity ◽  
Chelating Agent ◽  
Nitrilotriacetic Acid ◽  
Clotting Time ◽  
Coagulation Time

SummaryThe heparinoid G31150-A and nitrilotriacetic acid (NTA) were compared with heparinoid G31150 and heparin. In vitro the anticoagulant activity of NTA was 1/20000, G31150-A 1/8th and G31150, 1/10th of heparin. On intravenous injection in dogs, the degree and duration of hypocoagulability was about the same for the two heparinoids but less than predicted from the effects in vitro. Injection of 25 mg NTA/kg caused a slight increase in coagulation time lasting over 4 hours. When heparinoid G31150-A and NTA were given orally, there was an increase in clotting time of blood and metachromatic activity appeared in the urine. The greatest amount of activity was excreted with the highest dose of NTA alone. Microelectrophoresis of the urinary concentrate indicated the excreted material after NTA was not heparin, but another mucopolysaccharide; after G31150, a heparinoid. These results were confirmed by the resulting absorption spectrum of the dye obtained with added urinary concentrate. It is suggested that the effects produced when a chelating agent is given with oral heparin and heparinoids may be due to the release of a mucopolysaccharide.

Activation of Hageman Factor in Rat Anaphylaxis

1975 ◽  
Author(s):  
L. Fésüs ◽  
L. Muszbek
Keyword(s):  
Blood Clotting ◽  
Plasminogen Activators ◽  
Factor Xii ◽  
Clotting Time ◽  
Hageman Factor ◽  
Kaolin Clotting Time ◽  
Aggregation Of Platelets ◽  
Recalcification Time

At various intervals after antigen injection assays concerning haemostatic parameters were carried out in anaphylactic shock of rats pretreated with Bordetella Pertussis Vaccine. These were as follows: measurement of whole blood clotting time, recalcification time, partial thromboplastin time, kaolin clotting time in siliconised tubes, determination of the level of factor XII, measurement of plasminogen activator level, in vitro aggregation of platelets. The different clotting times shortened and the aggregation of platelets was inhibited within the first three-four minutes. The clotting times lengthened, the level of plasminogen activators increased, the level of factor XII decreased during the further minutes. These results and their comparison with that of produced by ellagic acid injection suggest that during anaphylaxis of rats the activation of Hageman factor takes place, which is followed by its partial consumption.

Correlation Between Cellular Functions and Morphological Changes of Human Trophoblast in Vitro

1975 ◽  
Vol 33 ◽  
pp. 600-601
Author(s):  
John C. Garancis ◽  
Robert O. Hussa ◽  
Michael T. Story ◽  
Donald Yorde ◽  
Roland A. Pattillo
Keyword(s):  
Electron Microscopy ◽  
Cellular Proliferation ◽  
Morphological Changes ◽  
Culture Fluid ◽  
Cellular Functions ◽  
Human Trophoblast ◽  
Transmission Electron ◽  
Marked Activity ◽  
Malignant Trophoblast

Human malignant trophoblast cells in continuous culture were incubated for 3 days in medium containing 1 mM N6-O2'-dibutyryl cyclic adenosine 3':5'-monophosphate (dibutyryl cyclic AMP) and 1 mM theophylline. The culture fluid was replenished daily. Stimulated cultures secreted many times more chorionic gonadotropin and estrogens than did control cultures in the absence of increased cellular proliferation. Scanning electron microscopy revealed remarkable surface changes of stimulated cells. Control cells (not stimulated) were smooth or provided with varying numbers of microvilli (Fig. 1). The latter, usually, were short and thin. The surface features of stimulated cells were considerably different. There was marked increase of microvilli which appeared elongated and thick. Many cells were covered with confluent polypoid projections (Fig. 2). Transmission electron microscopy demonstrated marked activity of cytoplasmic organelles. Mitochondria were increased in number and size; some giant forms with numerous cristae were observed.

The development of dormancy in bulblets of Lilium speciosum generated in vitro. II. The effect of temperature

1990 ◽  
Vol 80 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Isabelle Delvallee ◽  
Annie Paffen ◽  
Geert-Jan De Klerk
Keyword(s):  
Effect Of Temperature ◽  
Lilium Speciosum

Effect of Temperature on ADP-Induced Platelet Aggregation

1973 ◽  
Vol 29 (01) ◽  
pp. 183-189
Author(s):  
C. A Praga ◽  
E. M Pogliani
Keyword(s):  
Platelet Aggregation ◽  
Incubation Period ◽  
Room Temperature ◽  
Important Variable ◽  
Practical Significance ◽  
Effect Of Temperature ◽  
Induce Platelet Aggregation ◽  
Cuvette Holder ◽  
Exact Temperature

SummaryTemperature represents a very important variable in ADP-induced platelet aggregation.When low doses of ADP ( < 1 (μM) are used to induce platelet aggregation, the length of the incubation period of PRP in the cuvette holder of the aggregometer, thermostatted at 37° C, is very critical. Samples of the same PRP previously kept at room temperature, were incubated for increasing periods of time in the cuvette of the aggregometer before adding ADP, and a significant decrease of aggregation, proportional to the length of incubation, was observed. Stirring of the PRP during the incubation period made these changes more evident.To measure the exact temperature of the PRP during incubation in the aggre- gometer, a thermocouple device was used. While the temperature of the cuvette holder was stable at 37° C, the PRP temperature itself increased exponentially, taking about ten minutes from the beginning of the incubation to reach the value of 37° C. The above results have a practical significance in the reproducibility of the platelet aggregation test in vitro and acquire particular value when the effect of inhibitors of ADP induced platelet aggregation is studied.Experiments carried out with three anti-aggregating agents (acetyl salicyclic acid, dipyridamole and metergoline) have shown that the incubation conditions which influence both the effect of the drugs on platelets and the ADP breakdown in plasma must be strictly controlled.

Sign in / Sign up

Export Citation Format

Share Document