Method to determine aqueous protein concentration in vivo
Sawa, M.; Okuno, Y.; Okubo, A.; Shimizu, H.
Nippon Ganka Gakkai Zasshi 91(1): 102-106
1987
ISSN/ISBN: 0029-0203 PMID: 3591567 Document Number: 297244
We developed a new method to determine aqueous protein concentration in vivo. The instrument consisted of a light beam system with He-Ne laser tube and a biomicroscope with a photomultiplier. The laser power was 1.5 mW. We focussed the laser beam at a diameter of 50 .mu.m in the air and measured the intensity of the scattered light at the focussing area using photon counting method. Sampling time was 2 .times. 10-5 sec and total measurement time was 2 sec. We calculated the average photon counts per sampling times and defined it unit photon, which was treated as an index of protein concentration. In vitro study using bovine serum albumine and diluted human plasma solution, we had good correlation between the value for unit photon and albumine concentration ranging from 1 to 100 mg/ml and plasma diluting factors ranging from 250 to 10 times. In vivo study using rabbit eyes, we determined aqueous protein concentration before and after the paracentesis with both our method and Lowry's method. Secondary aqueous showed an increased protein concentration and their values determined by the two methods showed good accordance. We concluded that our method with laser beam to determine aqueous protein concentration in vivo was superior to other previous methods and useful in clinical application.