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J. Sebag, R.R. Ansari, K.I. Suh; Pharmacologic Vitreolysis with Microplasmin in Porcine Vitreous Evaluated by Dynamic Light Scattering . Invest. Ophthalmol. Vis. Sci. 2004;45(13):1945.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Pharmacologic Vitreolysis is a surgical adjunct that may also enable prophylactic vitreolysis to prevent disease. Previous studies using microplasmin have demonstrated its ability to induce PVD in animal models. The current studies employed a compact fiber–optic dynamic light scattering (DLS) device to characterize the molecular effects of this agent. Methods: Microplasmin (0.0125, 0.125, 0.25, 0.5, and 0.8 mg) was mixed with 60 µL of non–interacting 20nm polystyrene tracer nanospheres (10 % w/v) and 0.3 mL was injected into 17 post–mortem porcine eyes (4 controls, 13 experimental) via the pars plana. After 30–minutes at 370C, the anterior segment was surgically excised. DLS measurements were obtained at multiple sites along the optical axis from the anterior vitreous to the posterior pole (mean number of measurements =18.6, s.d =11.8) and across the entire vitreous along a horizontal axis 4 mm below the air/vitreous interface (mean number of measurements = 30.8, s.d.=18.0). All DLS measurements for each eye were averaged to represent a particle size index for the optical axis as well as the horizontal axis in that eye and the results were correlated with microplasmin dose. Results: There was a significant reduction in vitreous particle sizes with increasing doses of microplasmin. This was found in both the optical axis (coefficient of correlation = 0.92) and the horizontal axis (coefficient of correlation = 0.93). At the highest dose the reduction in normalized particle size was 91% (from 0.78 + 0.16 to 0.069 + 0.05) along the optical axis. Along the horizontal axis, the normalized particle size reduction was 86% (from 0.64 + 0.17 to 0.09 + 0.07). Conclusions: DLS is a powerful non–invasive technique by which to evaluate the molecular effects of pharmacologic vitreolysis. Microplasmin significantly reduces vitreous macromolecule size in a dose–dependent fashion. In consideration of these results and previous reports of this drug inducing vitreo–retinal separation, this agent seems suitable for testing in clinical pharmacologic vitreolysis.
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