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Biotech / Medical : QLT PhotoTherapeutics (QLTI) -- Ignore unavailable to you. Want to Upgrade?

To: John McCarthy who wrote (279)	3/7/1998 12:13:00 AM
From: JAMES BORECKI	Read Replies (1) \| Respond to of 1321

John, this article is very confusing! <<Results obtained to date confirm the noninvasive activation of PHOTOFRIN(R) by observation of lesions formed on the livers of PHOTOFRIN(R) treated laboratory mice. Lesions were formed by focusing a 730 nm beam through the skin of the mouse, onto the mouse liver. Lesions were well defined, with cell necrosis limited to the focal region of the activation beam. Microscopic examination of tissues confirmed localization of necrosis to the beam focus, and a notable absence of collateral damage. In contrast, substantial collateral damage was clearly observed in control animals treated with PHOTOFRIN(R) and activated using a single photon activation process with light at 630 nm. Additional experiments, designed to measure the increase in tissue temperature during exposure to laser irradiation, showed that light at 730 nm caused substantially less heating than light at 630 nm. Furthermore, tissue treated with 730 nm light alone (without PHOTOFRIN(R)) showed no detectable adverse effect. These results were made possible using Photogen's proprietary simultaneous two-photon activation process, which allows use of activation wavelengths that more easily penetrate tissue. Photogen's activation process further enables three dimensional control over the activation site.>> In the beginning of this paragraphe it says: <<Results obtained to date confirm the noninvasive activation of PHOTOFRIN(R)>> Later, at several points in the paragraph it says similar things to this: <<substantial collateral damage was clearly observed in control animals treated with PHOTOFRIN(R) To me it sounds like total contradiction. But I'm not in the medical profession, so if you or ANYONE can clarify what they are saying please let me know. Thanks in advance, JimB