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The purpose of this study is to obtain a reference range for a newly developed assay of ex vivo platelet COX-1 activity in normal volunteers taking a routine clinical dose of aspirin.
Aspirin has been shown to reduce cardiovascular events in at-risk individuals, but some aspirin-treated patients fail to exhibit expected changes in bleeding time and platelet aggregation. Recent evidence has correlated aspirin "non-response" to poor cardiovascular outcomes.
In order to study the mechanisms of aspirin resistance, an assay is needed to measure the catalytic activity of platelet cyclooxygenase (which should be inhibited by aspirin). A common assay in general use is the measurement of thromboxane B2 production in clotting whole blood. This measure, however, is influenced by genetic and environmental variations in the glass-activated coagulation pathway, albumin binding capacity, platelet activation pathways, arachidonic acid pools, and phospholipase activity.
Our laboratory has developed a direct assay of platelet cyclooxygenase (COX-1) activity that is not influenced by these variations. This study will generate a reference range in normal volunteers taking a routine clinical dose of aspirin (81mg daily) for this assay.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Chewable aspirin | Experimental | 81 mg daily for 2 weeks |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Chewable aspirin | Other | chewable aspirin 81mg daily for 2 weeks |
|
| Measure | Description | Time Frame |
|---|---|---|
| A Reference Range in Normal Volunteers Taking a Routine Clinical Dose of Aspirin (81mg Daily) for 2 Weeks | Determine the level of Thromboxane B2 at which patients with a result above are not fully inhibited, and patients with a TxB2 level below are fully inhibited. The reference range is the level of serum thromboxane at which participants below have fully inhibited COX-1 and participants above do not have fully inhibited COX-1 activity | 2 weeks |
| Measure | Description | Time Frame |
|---|---|---|
| Serum Thromboxane | SerumTxB2: They are formed from the prostaglandin endoperoxides and cause platelet aggregation, contraction of arteries, and other biological effects. | Baseline and at 2 weeks |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| John A Oates, MD | Vanderbilt University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Vanderbilt University | Nashville | Tennessee | 37232 | United States |
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| ID | Title | Description |
|---|---|---|
| FG000 | Chewable Aspirin | 81 mg daily for 2 weeks Chewable aspirin: chewable aspirin 81mg daily for 2 weeks |
| Title | Milestones | Reasons Not Completed | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
|
|
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| ID | Title | Description |
|---|---|---|
| BG000 | Chewable Aspirin | 81 mg daily for 2 weeks Chewable aspirin: chewable aspirin 81mg daily for 2 weeks |
| Units | Counts |
|---|---|
| Participants |
|
| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous | Median |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | A Reference Range in Normal Volunteers Taking a Routine Clinical Dose of Aspirin (81mg Daily) for 2 Weeks | Determine the level of Thromboxane B2 at which patients with a result above are not fully inhibited, and patients with a TxB2 level below are fully inhibited. The reference range is the level of serum thromboxane at which participants below have fully inhibited COX-1 and participants above do not have fully inhibited COX-1 activity | Posted | Number | 75% Confidence Interval | ng/ml | 2 weeks |
|
|
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Enteric-coated Aspirin | 81 mg daily for 2 weeks Enteric-coated aspirin: enteric-coated aspirin 81mg daily for 2 weeks |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Olivier Boutaud, PhD | Department of Pharmacology, School of Medicine, Vanderbilt University | 615-343-7398 | olivier.boutaud@vanderbilt.edu |
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| ID | Term |
|---|---|
| D001241 | Aspirin |
| ID | Term |
|---|---|
| D012459 | Salicylates |
| D062385 | Hydroxybenzoates |
| D010636 | Phenols |
| D001555 | Benzene Derivatives |
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| years |
|
| Sex: Female, Male | Count of Participants | Participants | No |
|
| Race (NIH/OMB) | Count of Participants | Participants |
|
| Region of Enrollment | Number | participants |
|
|
|
| Secondary | Serum Thromboxane | SerumTxB2: They are formed from the prostaglandin endoperoxides and cause platelet aggregation, contraction of arteries, and other biological effects. | Posted | Mean | Standard Error | ng/ml | Baseline and at 2 weeks |
|
|
|
| 0 |
| 64 |
| 0 |
| 64 |
| 0 |
| 64 |
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| D006841 |
| Hydrocarbons, Aromatic |
| D006844 | Hydrocarbons, Cyclic |
| D006838 | Hydrocarbons |
| D009930 | Organic Chemicals |