of intensive research. As of 2012 results have been converging on the hypothesis that the adverse cardiovascular effects are most likely due to inhibition of COX-2 in blood vessels, which leads to a decrease in the production of prostacyclin in them. Prostacyclin usually prevents platelet aggregation and vasoconstriction, so its inhibition can lead to excess clot formation and higher blood pressure. Research Research history The COX-2 enzyme was discovered in 1988 by Daniel Simmons, a Brigham Young University researcher. The mouse COX-2 gene was cloned by UCLA scientist Harvey Herschman, a finding published in 1991. The basic research leading to the discovery of COX-2 inhibitors has been the subject of at least two lawsuits. Brigham Young University has sued Pfizer, alleging breach of contract from relations BYU had with the company at the time of Simmons's work. A settlement was reached in April 2012 in which Pfizer agreed to pay $450 million. The other litigation is based on United States Pat. No. 6,048,850 owned by University of Rochester, which claimed a method to treat pain without causing gastro-intestinal distress by selectively inhibiting COX-2. When the patent issued, the university sued Searle (later Pfizer) in a case called, University of Rochester v. G.D. Searle & Co., 358 F.3d 916 (Fed. Cir. 2004). The court ruled in favor of Searle in 2004, holding in essence that the university had claimed a method requiring, yet provided no written description of, a compound that could inhibit COX-2 and therefore the patent was invalid. In the course of the search for a specific inhibitor of the negative effects of prostaglandins that spared the positive effects, it was discovered that prostaglandins could indeed be separated into two general classes that could loosely be regarded as "good prostaglandins" and "bad prostaglandins", according to the structure of a particular enzyme involved in their biosynthesis, cyclooxygenase. Prostaglandins whose synthesis involves the cyclooxygenase-I enzyme, or COX-1, are responsible for maintenance and protection of the gastrointestinal tract, while prostaglandins whose synthesis involves the cyclooxygenase-II enzyme, or COX-2, are responsible for inflammation and pain. The existing nonsteroidal anti-inflammatory drugs (NSAIDs) differ in their relative specificities for COX-2 and COX-1; while aspirin and ibuprofen inhibit COX-2 and COX-1 enzymes, other NSAIDs appear to have partial COX-2 specificity, particularly meloxicam (Mobic). Aspirin is ≈170-fold more potent in inhibiting COX-1 than COX-2. Studies of meloxicam 7.5 mg per day for 23 days find a level