Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0276640 (TEM)
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Endocytosis in lenses of rabbit and guinea pig was studied using freeze-fracture electron microscopy and horseradish peroxidase (HRP) as a macromolecular tracer during various periods of lens organ culture. Thin-section and freeze-fracture TEM show that endocytosis occurs predominantly in the epithelial cells of both rabbit and guinea pig lenses before incubation in the HRP. Tracer study in the guinea pig lens reveals that vesicular transport of HRP was most active in the epithelium and elongating young fiber cells where the metabolic activity is high. The endocytic vesicles, smooth in surface and about 0.07 microns in size, were frequently found associated with the lateral epithelial membranes. Isolated vesicles were seen to fuse with lysosomes to form multivesicular bodies or secondary lysosomes. The number of endocytic vesicles shows only a slight decrease after a 4-hr incubation, while secondary lysosomes gradually increase their number and reach the peak at the end of the culture period. The results suggest that endocytosis is a continuous physiologic process, and may play an important role in transporting some useful macromolecules from aqueous humor into the lens cells.
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PMID:Endocytosis of macromolecules in the lenses of guinea pig and rabbit. 248 73

The aim of the study is to prepare flurbiprofen axetil nanoemulsion-in situ gel system (FBA/NE-ISG) and observe its ocular pharmacokinetics, rheological behavior, TEM images, irritation and cornea retention. Production of nanoemulsion was based on high-speed shear and homogenization process, and then mixed with gellan gum to prepare FBA/NE-ISG. Rheological study showed that FBA/NE-ISG possesses strong gelation capacity and its viscosity and elastic modulus increases by 2 Pa*s and 5 Pa respectively when mixed with artificial tear at the ratio of 40 : 7. TEM images suggested no significant changes in particle morphology of the pre and post gelation. Good ocular compatibility of FBA/NE-ISG was testified by the irritation test based on histological examination. In vivo fluorescence imaging system was applied to investigate the characteristics of cornea retention, and the results indicated that the nanoemulsion-in situ gel (NE-ISG) prolonged the cornea retention time significantly since K(NE-ISG) (0.008 5 min(-1) was much lower compared with flurbiprofen sodium eye drops (FB-Na, 0.03% w/v) of which the K(Eye drops) was 0.105 2 min(-1), indicated that the cornea retention time of NE-ISG was prolonged significantly. Pharmacokinetics of FBA/NE-ISG in rabbit aqueous humor was studied by cornea puncture, the MRT (12.3 h) and AUC(0-12h) (126.8 microg x min x mL(-1)) of FBA/NE-ISG was 2.7 and 2.9 times higher than that of the flurbiprofen sodium eye drops respectively, which meant that the ocular bioavailability was improved greatly by the novel preparation. Therefore, FBA/NE-ISG can enhance the ocular bioavailability by prolonging drug corneal retention significantly. What's more, encapsulated by emulsion droplets prodrug flurbiprofen (FBA) instead of flurbiprofen (FB) can reduce the ocular irritation.
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PMID:[Ion-sensitive nanoemulsion-in situ gel system for ophthalmic delivery of flurbiprofen axetil]. 2135 61