Tissue targeted nanocapsids for oral insulin delivery via drink.

For the past eight decades, subcutaneous injection has been the main route used for supplementing the suboptimal insulin secretion for administering insulin as a treatment for diabetes mellitus. Although this method is effective, subcutaneous injections are painful, inconvenient and carry a high risk of infections leading to poor patient compliance. The insulin-encapsulated hepatitis E virus nanoparticle, composed of the noninfectious hepatitis E viral capsid, is expected to deliver insulin from the GI tract to the liver after ingestion. Hepatitis E virus nanoparticle could be the answer to the long search of effective and efficient means to administer insulin orally and the most preferred route of drug delivery with highest patient compliance.

Roles of silica gel in polycondensation of lactic acid in organic solvent.

Poly(lactic acid) is among the most important biodegradable, biocompatible polymers. To explore the feasibility of making poly(lactic acid) through potentially more selective enzymatic methods, the lipase-catalyzed direct polycondensation of lactic acid in organic solvents was investigated. At 37 degrees C the reaction was found to favor nonpolar solvents with larger log P values and smaller log S(w/o values. The addition of silica gel appeared to greatly enhance the lactic acid conversion (up to 98%) and the lipase stability under the reaction condition. However, upon further investigations, the silica gel itself was found to catalyze the polycondensation, in addition to the role of water removal. The conversion catalyzed by silica gel alone was actually higher than that by silica gel + lipase (or lipase alone). Up to 93% conversion of the acid functional group (or about 99.5% conversion of lactic acid monomer) was obtained in 120 h with silica gel as the catalyst. The finding is especially significant for interpreting (or reconsidering) the results of many presumably enzyme-catalyzed organic-phase reactions in the presence of silica gel.

Confocal and electron microscopic studies of laser subepithelial keratomileusis (LASEK) in the white leghorn chick eye.

OBJECTIVES: To evaluate the effect of 20% alcohol on the white leghorn chick cornea and to determine the confocal and electron microscopic findings of laser subepithelial keratomileusis surgery in the white leghorn chick corneal model. METHOD: Laser subepithelial keratomileusis surgery was performed on chick corneas and the morphologic changes were examined by transmission electron microscopy. Chick corneas were exposed to 20% alcohol for 30 and 45 seconds or 1 and 2 minutes (5 chicks per group) to evaluate the effect on the corneal epithelium. Photorefractive keratectomy using either mechanical or 20% alcohol-assisted debridement (5 chicks per group) was also performed. Keratocyte and epithelial cell deaths were analyzed 4 hours after surgery using terminal deoxynucleotidyl transfer-mediated biotin-dexoyuridine 5-triphosphate nick-end labeling (TUNEL) staining and transmission electron microscopy. RESULTS: Exposure of the corneal epithelium to 20% alcohol for 30 seconds or longer allowed reproducible separation of epithelial flaps in white leghorn chick eyes. Transmission electron microscopy immediately after alcohol treatment showed that exposure to 20% alcohol for 30 seconds or less had minimal adverse effects on the corneal epithelium. The TUNEL staining of corneas obtained 4 hours after surgery revealed TUNEL-positive cells in the central superficial stroma and more abundantly in the peripheral superficial stroma around the epithelial flap margin and in the epithelial flap itself, particularly in the basal epithelial layer. Transmission electron microscopy showed similar evidence of apoptosis in the epithelium and anterior stroma. CONCLUSIONS: The white leghorn chick eye seems to be a reasonable model for laser subepithelial keratomileusis surgery. Treatment with 20% alcohol for 30 seconds results in reproducible epithelial flap creation in the chick cornea and in relatively low levels of stromal and epithelial cell death after surgery.