Objective To study the mechanism of haze formation after photorefractive keratectomy (PRK). Methods 27 adult New Zealand white rabbits were employed in this study.24 of them received PRK in the right eye and laser in situ keratomileusis (LASIK) in the left eye at the same time and under the same condition for -10\^00D ablation at once,24hour,1 week,2 week,1month,3 month,6 month and 12 month after surgery,the corneas were examined periodically by slip\|lamp microscopy for haze formation,and the both eyes of 3 rabbits were enucleated,the corneas were studies with light microscopy;transmission electron microscopy;immunohistochemical evaluation for extracellular matrix,including collagen type Ⅰ,type Ⅲ,type Ⅵ,cellular fibronection,tenascin and laminin;RT\|PCR detection for mRAN of collagen type Ⅰ. Results The incidence of haze was 100% after PRK.No haze formation after LASIK.Haze was located at the anterior stroma immediately adjacent to the ablated areas.The change of structure and composition which correlated with haze formation was due to a combination of the following factors:the basement membrane of corneal epithelium was discontinuous;A new layer of subepithelium tissue was synthesized;fibroblast was increased in number and activated;the collagen fibrils were disorganized.The diameter of fibrils and the space between the fibrils were irregular in the anterior stroma;The newly synthesized extracellular matrix inculding collagen type Ⅰ,type Ⅲ,type Ⅵ,cellular fibronection,tenascin and laminin were deposited in the anterior corneal stroma.Conclusion\ The formation and disappearing of haze was the result of interreaction between fibroblast and extracellular matrix.The destruction of basement membrane of corneal epithelium and Bowmen's member after PRK is initializing factor during haze formation.\;[

Lysozyme generally exists in animals,plants and microorganisms,and it is used as a natural anti?infection materi?al and one of the important non?specific immune factors in organisms. This paper reviews the progress of researches on its classifi?cation,gene structure and function,and expression regulation in Oncomelania hupensis,and on the factors affecting its activi?ties in recent years,in order to further discuss its distribution in O. hupensis.

Objective To study the development of hereditary dystrophic retina of rd mice and photoreceptors apoptosis. Methods Retinal sections of rd mice and their controls at different ages ranging from postnatal days 5 to 40 were examined by morphological(light and electronic microscope), morphometric and TUNEL analysis. Results Compared with age-matched control mice, the retinal dystrophy of rd mice began at postnatal days 10, resulting in rapid loss of photoreceptors and reaching a peak at postnatal days 18. TUNEL postitive nucleus of photoreceptor cells emerged from postnatal days 10 and reached a peak at postnatal days 14 and 16. Ultrastructure of photoreceptor cell layer showed marked nuclear pyknotosis and chromatin margination. Apoptotic bodies of photoreceptor cells were observed.Conclusion Rd mice retina degenerated during the process of maturity. Photoreceptor cell death occurred through apoptosis.

Objective: To develop a method of retinal microglial cell culture to study the function of the microglial cell in diabetic retinopathy. Methods: Microglia were activated with LPS. Immunocytochemistry, con-focal microscopy, flow cytometry, MTT and ELISA were applied to observe the morphological characters, quantity, and functional changes of the microglia. Results: The purity of the microglia was up to 96% as determined by immunostaining and flow cytometry. Some morphological changes of microglia were observed after treatment with LPS, but their quantity kept stable. Cytokine TNF-? released from microglia increased significantly. Conclusion: The isolated microglial cells are pure by using this culture system, which would provide a valuable tool for studying mechanisms of microglial alterations in diabetic retinopathy.