Inhibition of thromboxane B2 formation of blood platelets by trapidil and other s-triazolo(l,5-a)pyrimidine derivatives

1987 ◽  
Vol 30 (2-3) ◽  
pp. 77-86 ◽  
Author(s):  
H.-U. Block ◽  
I. Hoffmann-Heinroth ◽  
Ch. Taube ◽  
M. Niebisch ◽  
H.-J. Mest
Keyword(s):  
Blood Platelets ◽  
Thromboxane B2 ◽  
Pyrimidine Derivatives

scholarly journals Radio Immunoassay of Thromboxane B2

1977 ◽  
Author(s):  
V. Ferraris ◽  
J. B. Smith ◽  
M. J. Silver
Keyword(s):  
Human Plasma ◽  
Silicic Acid Column ◽  
Blood Platelets ◽  
Cross Reactivity ◽  
Thromboxane B2 ◽  
Disease States ◽  
Rabbit Platelets ◽  
Normal Human ◽  
Radio Immunoassay ◽  
Normal Human Blood

Thromboxane B2 (TxB2) is one of the major end products of the cyclooxygenation of arachidonic acid (AA) in blood platelets, lung and certain other tissues. The immediate precursor of TxB2 is the unstable thromboxane A2 which has been reported to cause platelet aggregation and to constrict coronary arteries as well as the respiratory tree. We report here on the development of a novel radioimmunoassay for TxB2 in human plasma. Radioactive TxB2 was prepared by incubating 3H-AA3 (sp. act. = 64 Ci/mM) with a suspension of washed rabbit platelets for 10 min. at 37°C. The 3H-TxB2 in the lipid extract was subsequently purified by silicic acid column chromatography. Antibodies to TxB2 were generated by immunizing rabbits with TxB2 which had been coupled to albumin using 1,1’ – carbonyldimidazole. The binding of 3H-TxB2 to diluted plasma (final dilution – 1 /1500) from immunized rabbits was inhibited by authentic TxB2 (Nelson et al, Tetrahedron Letters No. 37, 1976) but not by prostaglandins. Thus, 1.5 picomoles of cold TxB2 caused 50% inhibition of the binding of 3H-TxB2 while no cross reactivity was observed with PGD2, PGE2 or PGF2α. Small amounts of TxB2 (10–50nM) were found in normal human plasma but large amounts (~500 nM) were found in sera obtained from normal human blood clotted at 37°C. The assay should be useful for determining plasma levels of TxB2 in various disease states. The work supported in part by Grant HL-14890 from the NIH. V.F. was funded by the U. S. Army (AR601–112).

Production of Thromboxane B2 and Thiobarbituric Acid-Reactive Substances by Human Blood Platelets

1980 ◽  
Vol 58 (2) ◽  
pp. 20P-20P
Author(s):  
P. B. B. Jones ◽  
L. C. Best ◽  
T. K. Holland ◽  
R. G. G. Russell
Keyword(s):  
Human Blood ◽  
Blood Platelets ◽  
Thiobarbituric Acid ◽  
Thromboxane B2 ◽  
Thiobarbituric Acid Reactive Substances ◽  
Human Blood Platelets

The Relationship between the Production of Thromboxane B2 and Malondialdehyde by Human Blood Platelets

1980 ◽  
Vol 59 (2) ◽  
pp. 131-135 ◽  
Author(s):  
L. C. Best ◽  
P. B. B. Jones ◽  
R. G. G. Russell
Keyword(s):  
Platelet Rich Plasma ◽  
Blood Platelets ◽  
Thromboxane B2 ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Thromboxane Synthetase ◽  
Malondialdehyde Formation ◽  
Induced Aggregation ◽  
The Relationship

1. The formation of thromboxane B2 and malondialdehyde was studied in human platelet-rich plasma, in gel-filtered platelets and in bovine platelet microsomes. 2. Exogenous sodium arachidonate was converted into thromboxane B2 and malondialdehyde in a concentration-dependent manner. Pre-incubation of platelets with aspirin inhibited the production of both thromboxane B2 and malondialdehyde, although malondialdehyde could apparently be detected in the absence of thromboxane B2. 3. The aggregating agents, thrombin, collagen and the ionophore A23187 also caused production of thromboxane B2 and malondialdehyde. ADP and adrenaline produced a smaller rise whilst the endoperoxide analogue U 46619 had only a slight influence on thromboxane and malondialdehyde, even though they all induced aggregation. 4. Pre-incubation of platelets with imidazole or 1-N-butylimidazole, which inhibit thromboxane synthetase, resulted in an inhibition of both thromboxane B2 and malondialdehyde formation in response to collagen. 5. The results indicate that thromboxane B2 and malondialdehyde are formed in parallel, in comparable quantities. However, under the conditions used in these studies, the apparent amounts of malondialdehyde exceed those of thromboxane B2, especially in the presence of exogenous arachidonate. Thus the thiobarbiturate reaction used to assay malondialdehyde may detect other products of lipid peroxidation. 6. Platelet thromboxane B2 concentrations did not always relate to the extent of aggregation. In particular, platelet aggregation could occur in the absence of detectable thromboxane B2 production.

3-D organization of fibrinogen receptors using computer reconstruction and whole-mount microscopy

1988 ◽  
Vol 46 ◽  
pp. 30-31
Author(s):  
E. T. O'Toole ◽  
R. R. Hantgan ◽  
J. C. Lewis
Keyword(s):  
Whole Blood ◽  
Colloidal Gold ◽  
Blood Platelets ◽  
Cell Contact ◽  
Computer Assisted ◽  
Adherent Cells ◽  
Differential Centrifugation ◽  
Computer Reconstruction ◽  
Sds Page ◽  
Whole Mount

Thrombocytes (TC), the avian equivalent of blood platelets, support hemostasis by aggregating at sites of injury. Studies in our lab suggested that fibrinogen (fib) is a requisite cofactor for TC aggregation but operates by an undefined mechanism. To study the interaction of fib with TC and to identify fib receptors on cells, fib was purified from pigeon plasma, conjugated to colloidal gold and used both to facilitate aggregation and as a receptor probe. Described is the application of computer assisted reconstruction and stereo whole mount microscopy to visualize the 3-D organization of fib receptors at sites of cell contact in TC aggregates and on adherent cells.Pigeon TC were obtained from citrated whole blood by differential centrifugation, washed with Ca++ free Hank's balanced salts containing 0.3% EDTA (pH 6.5) and resuspended in Ca++ free Hank's. Pigeon fib was isolated by precipitation with PEG-1000 and the purity assessed by SDS-PAGE. Fib was conjugated to 25nm colloidal gold by vortexing and the conjugates used as the ligand to identify fib receptors.

Ultrastructural Characteristics of Platelets Separated from Plasma by ADP-Induced Aggregation

1976 ◽  
Vol 34 ◽  
pp. 164-165
Author(s):  
B.A. Shinoda ◽  
M.D. Hardison ◽  
S.F. Mohammad ◽  
H.Y.K. Chuang ◽  
R.G. Mason
Keyword(s):  
Blood Platelets ◽  
Gel Filtration ◽  
Differential Centrifugation ◽  
Ultrastructural Characteristics ◽  
Induced Aggregation

The utilization of blood platelets in experimentation frequently requires their separation from blood and subsequent resuspension in media of known composition. Several methods are available for preparation of isolated platelets (1-3) by differential centrifugation or gel filtration, but most methods are tedious and time consuming. Often platelets obtained by use of such methods are in a state different functionally and ultrastructurally from that of platelets in plasma (4).Recently Mohammad, Reddick, and Mason (5) reported a method in which platelets were separated from plasma by ADP-induced aggregation, washed several times, and then incubated in a carefully selected medium that resulted in deaggregation of platelets.

Thrombus formation on artificial surfaces: Correlative microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 840-841
Author(s):  
Quintin J. Lai ◽  
Stuart L. Cooper ◽  
Ralph M. Albrecht
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Low Voltage ◽  
Thrombus Formation ◽  
Blood Platelets ◽  
Polymer Surfaces ◽  
Flow Conditions ◽  
Transmission Electron ◽  
Adhesion Of Platelets ◽  
Microscopic Techniques

Thrombus formation and embolization are significant problems for blood-contacting biomedical devices. Two major components of thrombi are blood platelets and the plasma protein, fibrinogen. Previous studies have examined interactions of platelets with polymer surfaces, fibrinogen with platelets, and platelets in suspension with spreading platelets attached to surfaces. Correlative microscopic techniques permit light microscopic observations of labeled living platelets, under static or flow conditions, followed by the observation of identical platelets by electron microscopy. Videoenhanced, differential interference contrast (DIC) light microscopy permits high-resolution, real-time imaging of live platelets and their interactions with surfaces. Interference reflection microscopy (IRM) provides information on the focal adhesion of platelets on surfaces. High voltage, transmission electron microscopy (HVEM) allows observation of platelet cytoskeletal structure of whole mount preparations. Low-voltage, high resolution, scanning electron microscopy allows observation of fine surface detail of platelets. Colloidal gold-labeled fibrinogen, used to identify the Gp Ilb/IIIa membrane receptor for fibrinogen, can be detected in all the above microscopies.

11-dehydro-thromboxane B2 enzyme immuno assay, a suitable screening assay for aspirin use?

2001 ◽  
Vol 120 (5) ◽  
pp. A596-A596
Author(s):  
M LEERDAM ◽  
F HUDIG ◽  
W ROOIJEN ◽  
E SLAATS ◽  
A GERAEDTS ◽  
...  
Keyword(s):  
Thromboxane B2 ◽  
Screening Assay ◽  
Immuno Assay ◽  
Enzyme Immuno Assay
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