Presence of snake-like chromatin in epithelial cells of keratoconjunctivitis sicca followed by a large number of micronuclei.

OBJECTIVE: To evaluate the number of micronuclei in snake-like chromatin (SLC) cells in the conjunctival epithelium of keratoconjunctivitis sicca (KCS) patients. To elucidate possible correlations between SLC cell numbers and KCS intensity. STUDY DESIGN: Impression cytology specimens from the bulbar conjunctiva of healthy controls and KCS patients were harvested and divided into 3 groups: group 1, controls; group 2, KCS SLC-negative; and group 3, KCS SLC-positive. The number of micronuclei (MNi) in SLC-negative and SLC-positive epithelial cells of each group was counted. RESULTS: The number of MNi in SLC-negative cells of groups 1 and 2 did not exceed 1 MNi/1,000 cells. A significant increase in the frequency of micronuclei in the upper bulbar conjunctiva was noted in SLC-positive (14.75 +/- 8.09 MNi/1,000 cells) as well as SLC-negative cells (4.0 +/- 3.83 MNi/1,000 cells) of group 3. CONCLUSION: We demonstrate here that the presence of MNi in the conjunctival epithelium of KCS patients could be a characteristic feature accompanying SLC cells. The fact that increased numbers of SLC cells correlates with impaired values in clinical test as well as decreased goblet and epithelial cell densities confirms that the presence of SLC cells correlates with KCS intensity.

Organ culture, but not hypothermic storage, facilitates the repair of the corneal endothelium following mechanical damage.

PURPOSE: To evaluate the reparative capacity of the mechanically injured endothelium of corneas stored under organ culture (OC) or hypothermic conditions. METHODS: The central endothelium of 12 pairs of human corneas with similar endothelial parameters was damaged to create a 1 mm(2) lesion. One cornea from each pair was stored under OC and one under hypothermic conditions. The endothelial cell density (ECD), coefficient of variation, hexagonality and percentage of dead cells were assessed before and after damage and on days 7, 14, 21 and 28 of storage. RESULTS: The mean ECD of corneas subsequently stored under OC or hypothermic conditions was 2764/mm(2). Immediately after damage, a denuded Descemet's membrane with a few remaining dead cells was observed at the injured area. After 7 days of storage under OC conditions, almost no dead cells were observed at the place of injury. A non-significant worsening of the qualitative parameters (polymegatism and pleomorphism) was found. After 14 days, ECD was 1933/mm(2) and 2478/mm(2) centrally and pericentrally, respectively. Similar values were found after 21 and 28 days of storage. The lesions with remnant dead cells persisted throughout hypothermic preservation. From day 14 the corneas became cloudy and in poor condition, while the pericentral ECD was 2523/mm(2). CONCLUSION: The reparative capacity of the cornea is maintained under OC but not under hypothermic conditions. For corneas containing dead endothelial cells, OC is therefore the method of choice because it may improve the quality of the stored tissue.