Alternative splicing of cyclooxygenase-1 mRNA in the human iris.

In homogenates of the human iris, the nonsteroidal anti-inflammatory drug (NSAID) S(+)flurbiprofen has been reported to inhibit cyclooxygenase-1 (COX-1) 70-fold more potently than in human whole blood. We hypothesized that this difference may be due to alternative splicing of COX-1 mRNA in the human iris or in whole blood. In this study, we have identified a similar COX-1 splice variant (COX-1SV) in both tissues with comparable COX-1/COX-1SV expression ratios. Therefore, we conclude that the difference in IC(50) values of S(+)flurbiprofen towards COX-1 in the human iris and human whole blood is not related to differences in the occurrence of spliced COX-1.

99mTc-diflunisal and the human iris: topical application reveals localization.

Following the instillation of a drug into the eye, drainage mechanisms will commence at once. In this report, an attempt was made to assess the dynamics of an instilled nonsteroidal anti-inflammatory drug (NSAID), diflunisal, labeled with 1 MBq 99mTc followed by twenty minutes of scintigraphy. The results obtained with this labeled drug were compared with instillation of the same volume and activity of 99mTcO4-. Although the pertechnetate anion is an excellent and innocuous indicator for detecting the external lacrimal drainage system of the eye, it cannot visualize the internal structures. A clear scintigraphic difference was noted between labeled diflunisal and the pertechnetate anion. Scintigraphic activity surrounding the pupil of the eye provides evidence of visualization of the iris/ciliary body. This seems reasonable as the cyclooxygenase enzyme is located in this structure, and NSAIDs exert their mechanism of action via this complex. With this technology, visualization of some internal structures of the eye may be facilitated.