The enigma of aspirin

A new effect of acetylsalicylic acid? Significantly lower prevalence of nasal carriage of Staphylococcus aureus among patients receiving orally administered acetylsalicylic acid

We aimed to evaluate effect of acetylsalicylic acid on the prevalence of nasal carriage of Staphylococcus aureus. Patients were orally administered a prophylactic dose of acetylsalicylic acid and then were compared with control subjects. The prevalence of nasal carriage of S. aureus was significantly lower among patients who received acetylsalicylic acid than among the control subjects (P<.001).

Reduction of bacterial titers by low-dose aspirin in experimental aortic valve endocarditis

Using a rabbit model of Staphylococcus aureus endocarditis, we studied the effects of aspirin on the natural progression of this infection. Compared with untreated animals, the aspirin-treated animals showed a 30% (P = 0.11) reduction in the weight of the vegetations and an 84% (P = 0.03) reduction in the bacterial titer of the vegetations.

The effects of varying doses of aspirin on human platelet activation induced by PAF, collagen and arachidonic acid

1. The effect of increasing doses of orally administered aspirin (30-900 mg) on platelet aggregation and ATP release induced by arachidonic acid (AA), collagen and platelet activating factor (PAF) was assessed in 12 normal volunteers. 2. Aspirin ingestion was associated with a significant increase in EC50 for AA (P less than 0.0001) and collagen (P less than 0.0001) but not for PAF (P greater than 0.495) although the normal biphasic aggregation response for the latter was abolished. Maximum ATP release was reduced by aspirin for all three agonists. 3. The mean maximum degrees of inhibition of platelet aggregation induced by aspirin for AA, collagen and PAF were 100%, 48% and 21% of baseline, respectively. The corresponding mean maximum inhibition of ATP release was 100%, 63% and 57%. The minimum cumulative doses of aspirin producing these effects were 240, 240 and 90 mg for AA, collagen and PAF respectively. For collagen alone, there was a significant decrease in the degree of inhibition of aggregation between the last dose on day 1 (150 mg) and the baseline measurement on day 2. 4. Platelets from female subjects were more sensitive to collagen (P less than 0.05) and AA (P less than 0.01) stimulation compared with males. However, prior to aspirin ingestion, PAF produced a greater maximum response in platelets from females (P less than 0.02) while following aspirin ingestion PAF-induced activation was inhibited to a greater degree in females (P less than 0.02). 5. These results indicate that collagen- and PAF-induced platelet activation are only partially dependent on cyclo-oxygenase and for PAF this seems related only to the second phase of aggregation.(ABSTRACT TRUNCATED AT 250 WORDS)