Using N,N,N’,N’-tetramethyl-p-phenylenediamine (TMPD) to Assay Cyclooxygenase Activity In Vitro

2009 ◽  
pp. 129-140 ◽  
Author(s):  
Nenad Petrovic ◽  
Michael Murray
Keyword(s):  
Cyclooxygenase Activity

A Thiazole Compound with Potential Antithrombotic Activity

1982 ◽  
Vol 47 (02) ◽  
pp. 173-176 ◽  
Author(s):  
E E Nishizawa ◽  
A R Mendoza ◽  
T Honohan ◽  
K A Annis
Keyword(s):  
Platelet Aggregation ◽  
Potent Inhibitor ◽  
Platelet Rich Plasma ◽  
Development Program ◽  
Antithrombotic Agent ◽  
Antithrombotic Activity ◽  
Thiazole Derivative ◽  
Cyclooxygenase Activity ◽  
Drug Development Program

SummaryA thiazole derivative, 4,5-bis(p-methoxyphenyl)-2-(trifluoromethyl)-thiazole was found to be a potent inhibitor of collagen-induced platelet aggregation, in vitro, using platelets from at least six species, including man. It was active in human platelet-rich plasma at a concentration of 1 ng/ml. While its antiplatelet activity was greater than that of flurbiprofen, its cyclooxygenase activity was equivalent to that of flurbiprofen. Also, compared to flurbiprofen, the thiazole had less anti-inflammatory activity in the hind-paw edema test. The thiazole derivative inhibited platelet aggregation following oral administration in five laboratory species. In the guinea pig it was active at 0.5 mg/kg. The LD50 in mice was greater than 1000 mg/kg (i.p.). This compound, which was designed through a systematic drug development program, may have high potential as an antithrombotic agent.

Kinetic analyses of the effects of hyperoxia and hypoxia on vascular cyclooxygenase activity in vitro

1984 ◽  
Vol 125 (1) ◽  
pp. 170-176 ◽  
Author(s):  
B.N. Yamaja Setty ◽  
Ronald W. Walenga ◽  
Marie J. Stuart
Keyword(s):  
Cyclooxygenase Activity

scholarly journals Monitoring the entry of new platelets into the circulation after ingestion of aspirin

Blood ◽  
1983 ◽  
Vol 61 (6) ◽  
pp. 1081-1085
Author(s):  
G Di Minno ◽  
MJ Silver ◽  
S Murphy
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Adenosine Diphosphate ◽  
Normal Subjects ◽  
In Vitro Experiments ◽  
Early Entry ◽  
Cyclooxygenase Activity ◽  
Aspirin Ingestion ◽  
Thromboxane Formation

There have been reports of a 24–48-hr delay in the recovery of platelet cyclooxygenase activity and platelet function after the ingestion of aspirin. However, these studies employed a single aggregating agent to stimulate enzymatic or functional activity. We investigated the effects of some pairs of aggregating agents on 14 platelet-rich plasmas (PRP) from normal subjects 2 and 4 hr after ingestion of 650 mg aspirin and daily up to 72 hr. We studied platelet aggregation and secretion with a lumiaggregometer and thromboxane-B2 formation by radioimmunoassay. Aggregation and secretion occurred as early as 4 hr after aspirin ingestion in response to combinations of arachidonic acid with epinephrine, collagen, or adenosine diphosphate (ADP). Thromboxane formation was detected as early as 4 hr after ingestion of aspirin in response to 1 mM arachidonic acid in combination with 1 microgram/ml collagen. Up to 72 hr, there was a linear return of thromboxane formation stimulated by this combination, reflecting the entry of new platelets into the circulation. In vitro experiments with mixtures of aspirin-free and aspirin-treated platelets showed that the combination of collagen and arachidonic acid (AA) could produce full aggregation and secretion when only 2.5% of aspirin-free platelets were present. Use of the combination of collagen plus AA demonstrates the early entry into the circulation of platelets originating from megakaryocytes whose cyclooxygenase has not been completely acetylated.

Cellular LTB4 production differs in allergic sheep with and without late airway responses

1990 ◽  
Vol 259 (2) ◽  
pp. L136-L143 ◽  
Author(s):  
G. A. Chapman ◽  
F. Signoretti ◽  
I. T. Lauredo ◽  
P. Torrealba ◽  
M. W. Sielczak ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Peripheral Blood ◽  
High Performance ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Cyclooxygenase Activity ◽  
Ltb4 Production ◽  
Airway Responses

We tested the hypothesis that allergic sheep that develop both early and late airway responses to inhaled Ascaris suum antigen (late responders) have an increased capacity to generate leukotrienes (LTs) compared with allergic sheep that show only early responses to inhaled antigen (acute responders). To test this hypothesis, we measured LTB4 production, in vitro, by granulocytes isolated from peripheral blood and by macrophages isolated from bronchoalveolar lavage (BAL) from both groups of sheep greater than or equal to 2 wk after the animal's last antigen challenge; LTB4 production by granulocytes isolated from BAL from both groups of sheep 6 and 48 h after local airway challenge with A. suum antigen was also measured. LTB4 production was induced by incubating cells (i.e., either granulocytes or macrophages) with calcium ionophore (A23187, 2 microM) and arachidonic acid (30 microM). LTB4 production was quantitated by high-performance liquid chromatography and verified by radioimmunoassay (RIA). On stimulation peripheral blood granulocytes from late responders (n = 7) produced (means +/- SD/10(6) cells) 13.3 +/- 5.2 ng LTB4 compared with 5.3 +/- 1.5 ng LTB4 (P less than 0.05) for acute responders (n = 7). This increased LTB4 production did not result from variations in granulocyte differential or cyclooxygenase activity (as indicated by RIA measurements of prostaglandin E2 production).(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro effects of nonsteroidal anti-inflammatory drugs on cyclooxygenase activity in dogs

2000 ◽  
Vol 61 (7) ◽  
pp. 802-810 ◽  
Author(s):  
Patricia Kay-Mugford ◽  
Sally J. Benn ◽  
Jonathan LaMarre ◽  
Peter Conlon
Keyword(s):  
Cyclooxygenase Activity ◽  
Inflammatory Drugs ◽  
Anti Inflammatory ◽  
In Vitro Effects
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