The Effect of RGP Lens and Reverse Geometry Lens on Corneal Epithelial Proliferation Rate in Rabbit

PURPOSE: To investigate proliferation rate of the corneal epithelium with rigid gas permeable lens(RGP) or reverse geometry lens(RGL) wearing. METHODS: Twenty-four rabbits were fitted with either a RGP or RGL on right eye, with left eye serving as a control. They were sacrificed at 1, 3, 7, and 14 days after lens fitting. after immunohistochemistry using 5-bromo-2-deotyuridine, BrdU-labeled cells were counted in 10-medium power fields (X200) in each sample using light microscope by 1.0 mm intervals between superior limbus and the center. RESULTS: The number of BrdU-labeled cells was highest in peripheral cornea, and lowest in limbus(p<0.05). The BrdU-labeled cells of limbus increased by 127% but labeled-cells of the center decreased by 24% in RGP group after 1-day fitting. Increase of the labeled cells was observed in the mid-peripheral and central cornea by 12% and 121% each but the decrease of labelled cells was found at the limbus by 16% in RGL fitting group at 1 day. After 14days, Both RGP and RGL group showed decrease of BrdU-labeled cells in limbus by 8% each, and in the center by 32% and 63%, respectively. CONCLUSIONS: Normal rabbit cornea was characterized by different epithelial proliferation rates according to location. However these pattern was significantly altered with both RGL and RGP fitting group. The change was greater in RGL group than in RGP group. This suggested wearing the RGL might be less physiologic than RGP fitting.

The Effect of RGP Lens and Reverse Geometry Lens on Apoptosis in Rabbit Cornea

PURPOSE: To investigate the cytotoxic effect of rigid gas permeable(RGP) and reverse geometry lens(RGL) on rabbit corneal cells. METHODS: In 36 white rabbits, right eyes were worn with either RGP or RGL. Left eyes were served as control. The rabbits were sacrificed at 1, 3, 7, 14 days after fitting and 7, 14 days after removal. Morphological changes of the basal epithelial cells and stromal keratocytes were observed using the light and transmission electron microscopy. The samples were examined after TUNEL staining in 3 high power fields (x400). RESULTS: In control eyes, 2.26% of central corneal epithelial cells showed apoptosis. After RGP wearing, the epithelial apoptosis decreased by 0.32% compared to control eyes(2.17%) at 14 days(p<0.001), and returned to 1.55% at 14 days after lens removal(2.04% in control, p=0.161). After RGL wearing, the degree of apoptosis was also lower than control(3.22%) by 0.30% at 14 days(p=0.003). However, it increased to 0.75% at 14 days after lens removal(1.67% in control, p=0.077). A few TUNEL positive fibroblasts were found in superficial stroma in both RGP and RGL group, but not in control eyes. CONCLUSIONS: Both RGP and RGL wearing may decrease the degree of apoptosis in corneal epithelium and lead the apoptosis in corneal stroma. The degree of apoptosis was recovered after lens removal, suggesting the process might to be reversible. The fitting with RGL induced apoptosis of keratocyte more than the fitting with RGP did. It suggests that the RGL wearing may be less physiologic than RGP wearing.

Solitary Fibrous Tumor A clinicopathologic review of five cases

We experienced five cases of solitary fibrous tumor; two in the pleura, two in the orbital soft tissue, and one in the lung parenchyma. Three patients were male, and the age of the patients ranged from 38 to 71 years (mean age: 53.6). Grossly, the masses were well circumscribed and had varying sizes from 2.5 to 30.0 cm. The cut surfaces were grayish-yellow firm with focal variegated hemorrhage, necrosis, cystic change, and myxoid area. Microscopically, these were characterized by a haphazard proliferation of spindle cells or polygonal cells separated by variable amounts of hyalinized collagen and showed a prominent vascular channels reminiscent of hemangiopericytoma in foci. Immunoperoxidase stains showed a strong reactivity for CD34, and were weakly positive for vimentin. Electron microscopical examination revealed features of fibroblast; spindle to round tumor cells were arranged in groups and surrounded by collagen. Nucleoli were seldom prominent. The cytoplasm contained many microfilaments and a moderate number of cisternae of rough endoplasmic reticulum.