[The effect of Sairei-to on oxygen-induced retinal neovascularization in the neonatal rat].

PURPOSE: To study the effect of Sairei-to (ST), a Japanese traditional medicine, on oxygen-induced retinopathy (OIR) in rats. METHODS: OIR was induced by maintaining Sprague-Dawley neonatal rats in 80% oxygen for 12 days. The rats were treated once daily with oral administration of 0.75 g/kg (n = 9), 1.5 g/kg (n = 13) of ST in water, or water alone (WA, n = 13) at 5 mL/ kg body weight from day 6 to day 17. On day 18, retinal samples were collected. Retinal neovascularization (NV) was assessed by the NV score, and by the percentage of avascular area (% AVA), using a method previously reported. The number of severe retinal NV cases (NV > or = 9) was compared. The retinal vascular endothelial growth factor (VEGF) concentrations were measured with an immunoassay kit, at 0, 12, 24, 72 and 144 hours after oxygenation. RESULTS: NV score and % AVA decreased in the ST treated group compared to the WA group. However, severe NV was seen in five cases of WA and in one case of the ST treated group. Thus severe NV was inhibited significantly by ST treatment (p = 0.0185). Retinal VEGF did not differ between groups at any time points. CONCLUSION: These data suggest that severe NV in OIR is inhibited by ST treatment.

Phase behavior of a mixture of poly(isoprene)-poly(oxyethylene) diblock copolymer and poly(oxyethylene) surfactant in water.

The phase behavior of a mixture of poly(isoprene)-poly(oxyethylene) diblock copolymer (PI-PEO or C250EO70) and poly(oxyethylene) surfactant (C12EO3, C12EO5, C12EO6, C12EO7, and C12EO9) in water was investigated by phase study, small-angle X-ray scattering, and dynamic light scattering (DLS). The copolymer is not soluble in surfactant micellar cubic (I1), hexagonal (H1), and lamellar (Lalpha) liquid crystals, whereas an isotropic copolymer fluid phase coexists with these liquid crystals. Although the PI-PEO is relatively lipophilic, it increases the cloud temperatures of C12EO3-9 aqueous solutions at a relatively high PI-PEO content in the mixture. Most probably, in the copolymer-rich region, PI-PEO and C12EOn form a spherical composite micelle in which surfactant molecules are located at the interface and the PI chains form an oil pool inside. In the C12EO5/ and C12EO6/PI-PEO systems, one kind of micelles is produced in the wide range of mixing fraction, although macroscopic phase separation was observed within a few days after the sample preparation. On the other hand, small surfactant micelles coexist with copolymer giant micelles in C12EO7/ and C12EO9/PI-PEO aqueous solutions in the surfactant-rich region. The micellar shape and size are calculated using simple geometrical relations and compared with DLS data. Consequently, a large PI-PEO molecule is not soluble in surfactant bilayers (Lalpha phase), infinitely long rod micelles (H1 phase), and spherical micelles (I1 phase or hydrophilic spherical micelles) as a result of the packing constraint of the large PI chain. However, the copolymer is soluble in surfactant rod micelles (C12EO5 and C12EO6) because a rod-sphere transition of the surfactant micelles takes place and the long PI chains are incorporated inside the large spherical micelles.